# Issue 5, 2017

## Calculation of the sound fields in the environment model including simultaneously atmosphere, water and bottom

## Calculation of the sound fields in the environment model including simultaneously atmosphere, water and bottom

### K. V. Avilov$^{1,2}$, S. N. Kulichkov$^2$, O. E. Popov$^2$

This report introduces the description of the program package for calculation of the broadband transfer functions of the environment model including atmosphere, water column and bottom taking into account the dependence of the medium acoustic properties both on vertical and horizontal coordinates by the pseudodifferential parabolic equation technique in one-way approximation without taking into account shear stresses. Calculation examles are included both verifying the package functionality and having some applicable interest.

Show Abstract## Observation of stable components of sound fields in field measurements in Lake Ladoga

## Observation of stable components of sound fields in field measurements in Lake Ladoga

### P. V. Artel'nyi, A. L. Virovlyansky, A. Yu. Kazarova, P. I. Korotin, L. Y. Lyubavin, A. V. Stulenkov

Spatio-temporal structures of sound fields in Lake Ladoga were measured using an extended vertical receiving array. Results of processing of these data are presented. The processing was aimed at extracting such field components which are stable with respect to unavoidable inaccuracy of the environmental model. In terms of a ray-based approach the stable compo-nent is formed by a narrow beam of rays. In terms of the normal mode approach it is formed by a small group of modes. In the experiment under consideration, wave fields excited by a point source emitting wideband sound pulses and fields of wave beams excited at fixed fre-quencies using a vertical emitting array were analyzed. Comparison of results of the data processing and computed wave fields shows that, as expected, the stable components can be predicted more accurately that the total sound field.

Show Abstract## Some peculiarities of sounds generated by snapping shrimps in the Black Sea.

## Some peculiarities of sounds generated by snapping shrimps in the Black Sea.

### N. G. Bibikov

During autumn period of 2015-2016 intensive bionoises were recorded in shallow waters of the eastern coast of the Black Sea (Suhum bay) using broadband hydrophone (upper frequency limit - a few hundred kilohertz). When placing a hydrophone in 30-40cm above the bottom surface at a depth of 5 to 10 m the recorded signal contained high frequency noise generated by snapping shrimps. Along with these background signal we observed relatively rare (usually several times per minute), but very intense (up to a few hundred Pa) clicks. They apparently were radiated by single shrimp localized in the vicinity of the hydrophone. Such conditions are allowed to carry out a time-frequency analysis of the signals in natural conditions of the habitat. It has been shown that they consist of the following sections: a short precursor generated by the water jet emitted during the closing of the claws, a powerful ultrasound pulse arising due to the collapse of a cavitations bubble, and multiple reflections from the surrounding elements of the bottom surface (gravel, empty shells of mussels). The rise time of the main pulse may be 7-10 microseconds with total duration of the signal from 0.1 to 0.4ms, varying specificity due to reflections. In many cases along with the main pulse the delayed echo from local artificial underwater objects and from the surface also can be observed. The possible practical applications of the data are discussed.

Show Abstract## 3D-printing possibilities for the manufacturing technology development of hydroacoustic longitudinal bending type emitters with the complex radiator's body geometry

## 3D-printing possibilities for the manufacturing technology development of hydroacoustic longitudinal bending type emitters with the complex radiator's body geometry

### A. K. Britenkov$^{1,2}$, B. N. Bogolybov$^1$, S. A. Smirnov$^1$, V. A. Perfilov$^1$

Low-frequency hydroacoustic emitters are being used in a wide range of tasks: from long-distance sound communication and remote control to seismoacoustic reconnaissance. Thus the manufacturing of compact high-power radiators emitting in a sufficiently wide frequency band is an actual task. Making the radiator shell is one of the most laborious and complicated technological operations in the process of creating and customizing hydroacoustic transducers. Unrealizable for the ordinary metalworking complex shapes of radiator's body can be produced by layering laser melting (SLM-technology). Making the radiator shell longitudinal bending-type piezoelectric active element by laser 3D-printing of metal powders eliminates the problem of encapsulation, resistance to hydrostatic pressure and reduce the parameters dispersion of the radiator to facilitate its configuration, as well as improve reliability of the transducer.

Show Abstract## On the scattering of high frequency sound in the upper layer of the ocean

## On the scattering of high frequency sound in the upper layer of the ocean

### V. A. Bulanov, A. V. Storozhenko

The results of researches of sound scattering in the upper layer for different regions of the ocean are presented and the main differences of sound scattering in the upper layer of the Arctic seas and in the Equatorial and mid-latitude ocean are shown. The features of distribution of sound-scattering layers on the continental shelf of the Sea of Japan in different seasons of the year were analyzed. Simultaneous studies of sound scattering and netting the fish collection of the plankton in situ allowed us to identify the relationship between the scattering of high frequency sound and distribution of zooplankton.

Show Abstract## The propagation of pulsed pseudo-random signals from the shelf into the deep sea during the winter hydrological conditions of the Japan Sea

## The propagation of pulsed pseudo-random signals from the shelf into the deep sea during the winter hydrological conditions of the Japan Sea

### A. V. Burenin, Yu. N. Morgunov

The article discusses the results of an experiment conducted in the Japan sea in March 2016 on the acoustic track length of 194 km at the winter hydrological conditions. It was the most complicated case of propagation of pulsed pseudo-random signals from the shelf into the deep sea in the presence of acoustic track the vortex formation. Analysis of experimentally obtained impulse response showed that apparent at all points in the maximum first arrival of acoustic energy is in good agreement with the calculation. This suggests that the horizon of reception of the first pulses come, the past in the near-surface sound channel at the shortest distance and at small, close to zero angles.

Show Abstract## Joint reconstruction of water and bottom parameters in shallow sea by mode tomography methods

## Joint reconstruction of water and bottom parameters in shallow sea by mode tomography methods

### A. I. Vedenev$^1$, V. V. Goncharov$^1$, P. Yu. Mukhanov$^2$, S. N. Sergeev$^2$, A. S. Shurup$^2$

In this article a 2-dimentional model of shallow sea tomography is regarded for the joint reconstruction of waveguide parameters in a water layer and in a bottom using modes’ time delays as initial data. Linear approximation is used for the inversion of initial data and correction of the estimates is implemented in iteration cycle. The results of numerical simulation for the joint reconstruction of sound speed profile, flows and bottom properties by using the regarded scheme are presented.

Show Abstract## Research unidirectional reception, evaluation range and source depth using scalar and vector-scalar antennas

## Research unidirectional reception, evaluation range and source depth using scalar and vector-scalar antennas

### G. M. Glebova$^1$, G. N. Kuznetsov$^2$

We analyze the spatial spectra at the output of the linear scalar or vector-scalar antenna (SA or VSA) at signal processing methods having a different resolution, consistent or inconsistent with the transfer function of the waveguide. The experiments were conducted in a shallow pool at the stationary location of the antenna and the emitter and in regime of the towing with the moving noise source. VSA, unlike SA, suppresses signals coming on «mirror» petals and has unidirectional direction finding, and at using consistent processing in passive mode uniquely determines the distance and the depth of the source.

Show Abstract## Low frequency pulses propagation in the Ocean

## Low frequency pulses propagation in the Ocean

### V. N. Golubev, I. P. Smirnov

Experimental data of low frequency pulse signals propagation in a region of Pacific Ocean are represented. Calculations of the signal space-temporal structure and intensities of bottom re-flections were performed in the geometric acoustical approach. For two models of the wave-guide satisfactory accordance between experimental and theoretical results were received. This allows to estimate the characteristics of the bound and the effective waveguide depth for the range of frequencies in 5-40 Hz. Keywords: pulse signal, space-temporal structure, intensity, deep ocean channel, geometric acoustics approach

Show Abstract## Acoustic fields in the layered gas-saturated medium

## Acoustic fields in the layered gas-saturated medium

### B. I. Goncharenko, V. A. Gusev

The propagation of acoustic waves and bounded beams in layered inhomogeneous medium containing gas bubbles is studied. Such system models, in particular, the acoustic processes in freshwater ponds bottom soil that contains gas-saturated sedimentary rocks. It is shown that the sound speed in gas-saturated soil is determined by amount of containing gas. If amount of gas increase to about 1% of the total volume of sediment the sound speed drops to 100 m/s, i.e. in 15 times in comparison with the sound speed in water. The reflection and transmission coefficients of acoustic waves from layered gas-saturated medium and their dependence on frequency and angle of wave incidence are calculated. A comparison with the experimental results is made. It is shown that the frequency dependence of the module of the sound reflection coefficient received at one of the areas of the Klyazminsky reservoir, has an oscillating character, and the oscillation frequency depends on the thickness of gas-saturated layer and does not depend on the incidence angle. The possibility of recovery of the structural parameters of layered soil on this frequency dependence is shown. Nonlinear acoustic effects associated with a strong structural nonlinearity of a liquid with bubbles are studied. Different cases of the sound source location relative to the bottom soil boundary are considered and evolution equations for the cases of horizontal and oblique propagation of intense waves are derived. Wave profiles and the transverse form of beams are calculated.

Show Abstract## Some results of research of temporal variability of hydroacoustic noise in the Peter the Great Gulf of the Sea of Japan

## Some results of research of temporal variability of hydroacoustic noise in the Peter the Great Gulf of the Sea of Japan

### S. V. Gorovoy

The report describes the results of a study of temporal variability of AR and APMA models hydroacoustic noise at time intervals up to two minutes, registered using a single non-directional hydrophone in calm weather in the shallow zone near the port of Vladivostok. The report describes the dependences of AR(5) and ARMA(3,2) models from time. Results can be considered typical for the water area when no moving or at anchor vessels. The report summarizes the results of comparison of temporal variability of parameters for the AR(5) and ARMA(3,2) hydroacoustic noise models and the software-implemented model of white noise.

Show Abstract## Sound attenuation in shallow water with the bottom in the form of a gas-filled sediment layer overlaying permafrost

## Sound attenuation in shallow water with the bottom in the form of a gas-filled sediment layer overlaying permafrost

### V. A. Grigorev$^1$, V. G. Petnikov$^2$, A. V. Shatravin$^3$

Within the framework of numerical modeling the feasibility of mode description of the sound field is analyzed for shallow water with an Arctic type bottom: a liquid gas-filled sediment layer overlaying an elastic half-space (permafrost). It is determined that the optimum description of the field in the water layer at short distances from the sound source (order of 1÷10 depths of the waveguide) is achieved by using of the discrete spectrum of normal modes and quasi-modes calculated with use of the Pekeris cut. Computations of the transmission loss in the waveguide with the sediment layer thickness comparable to or higher than the acoustic wavelength in the sediments, shown that the seabed is acting as a uniform liquid half-space. If the thickness of the sedimentary layer is less than a quarter of the wavelength, then the layer can be neglected. The transmission loss abruptly increases with the sound speed in the sediments approaching the sound speed in the water. A method is proposed for estimating the sound speed in the sediment layer. The method based on the analysis of attenuation of the sound fields of higher modes.

Show Abstract## Investigation of peculiarities of low-frequency noises' spectral-correlation characteristics in shallow sea for purposes of passive tomography

## Investigation of peculiarities of low-frequency noises' spectral-correlation characteristics in shallow sea for purposes of passive tomography

### A. V. Grinyuk$^1$, V. N. Kravchenko$^1$, P. Yu. Mukhanov$^2$, I. R. Sabirov$^2$, S. N. Sergeev$^2$, A. S. Shurup$^2$

Results of the correlation processing for the low-frequency noise recorded in the Barents Sea by spatially separated bottom hydrophones are considered. Comparison of experimental data with results of numerical simulation shows that the inter-mode interference may play a significant role in the formation of the spectral-correlation characteristics of low-frequency noises, but not only the presence of the stationary phase point near the minimum of the dispersion curves of the group velocities for the different modes, as it was assumed before. It is demonstrated that the filtration of the frequency range, where the noise field is formed only by the lowest mode, makes it possible to increase the output signal-to-noise ratio in correlation processing that can be used during the development of passive tomography schemes.

Show Abstract## On local effect of low-frequency sound field mode coupling in randomly-inhomogeneous two-dimensional shallow sea

## On local effect of low-frequency sound field mode coupling in randomly-inhomogeneous two-dimensional shallow sea

### O. E. Gulin, I. O. Yaroshchuk

Statistical problem of a low-frequency sound propagation in shallow-sea waveguide with two-dimensional random inhomogeneities is considered. Transmission loss law for average intensity in the case of fluctuating thermocline and absorbing liquid bottom is investigated. Within the framework of local-mode approach it is shown that mode coupling with the distance is of local character if there are no strong fluctuations of modal wavenumbers in stochastic waveguide. So, in the local-mode approach the mode coupling to be the certain supplement to adiabatic approximation of intensity, and it does not change seriously the average transmission loss. Comparison between results of local-mode and diffusion approximation is also carried out.

Show Abstract## Effects of Wind Waves on Horizontal Array Gain in Shallow-Water Conditions

## Effects of Wind Waves on Horizontal Array Gain in Shallow-Water Conditions

### N. A. Zavolsky, A. I. Malekhanov, M. A. Raevsky, A. V. Smirnov

The paper is aimed at the comparative study of the wind-induced effects on the large horizontal array gain in shallow-water channels for several signal processing techniques, optimal ones included. Computer simulation is performed for some environmental conditions typical for the Barents Sea in the winter season and the Pierson-Moskowitz model for developed wind waves. The results obtained exhibit considerable effects of multiply sound scattering on the array gain and its essential dependence on the array size, propagation distance and wind speed.

Show Abstract## Significant horizontal inhomogeneities of the noise field in the ocean

## Significant horizontal inhomogeneities of the noise field in the ocean

### K. B. Ilich

Horizontal inhomogeneities of the ocean medium lead to horizontal inhomogeneities of the noise field. We looked at the inhomogeneities caused by the cold eddies and ocean bottom’s break ups. In addition noise sources on the ocean surface are considered to be horizontally homogeneous. Thus, effects connected with specifics of noise propagation in the complex ocean medium are analyzed. Radiation transfer theory is used successively for noise fields calculation. It is considered that the noise is more prominent in the water waves lines and almost absent in the waves lines reflected from the ocean bottom (ground wave lines).

Show Abstract## Methods of vibration protection of vector sensors

## Methods of vibration protection of vector sensors

### V. I. Korenbaum

The problem of vibration protection of vector sensors results from the increased vibration sensitivity of this class of hydroacoustic sensors. Vibration isolation, vibration compensation, and intensimetry vibration suppression are potentially suitable for vibration protection of vector sensors. The possibilities and limitations of these methods are considered depending on a value of the natural frequency of suspension, construction features of vector sensors of inertial and force types. Original technical solutions are developed.

Show Abstract## Dynamic routing protocol for autonomous underwater hydroacoustic buoy networks

## Dynamic routing protocol for autonomous underwater hydroacoustic buoy networks

### O. Yu. Kochetov$^1$, V. G. Petnikov$^2$, A. V. Shatravin$^1$

The peculiarities of the application of dynamic routing protocols for the design of a self-organizing network of autonomous underwater hydroacoustic buoys with underwater acoustic communication are discussed. A review of known dynamic routing protocols for mobile radio networks is presented, the advantages and disadvantages of proactive and reactive approaches are shown. Modifications of the AODV dynamic routing protocol for applying to underwater acoustic communication are proposed for Arctic shelf.

Show Abstract## Methods to improve immunity noise detection and direction finding using a vector-scalar modules

## Methods to improve immunity noise detection and direction finding using a vector-scalar modules

### G. N. Kuznetsov$^1$, A. F. Kurchanov$^2$

Made direction finding of broadband sources of scalar antenna (SA) and vector-scalar modules (VSM) using processing the flow of power and the new method based on the use of pseudovectors built on the projection of vector vibrational rate (VVV). Investigated method of interference suppression from a local source with using of vector fields.

Show Abstract## The using of spectrogram for noise source localization in shallow sea

## The using of spectrogram for noise source localization in shallow sea

### G. N. Kuznetsov$^1$, V. M. Kuz’kin$^1$, S. A. Pereselkov$^{1,2}$, I. V. Kaznacheev$^2$

The specifications of spectrum of a moving sound noise source when spectrogram is can be used for the localization problem is discussed. The localization algorithm is presented. The noise immunity is estimated. The results of numerical and natural experiments are analyzed.

Show Abstract## Simulation of the array gain in an ocean waveguide for the multimode signal against the modal noise

## Simulation of the array gain in an ocean waveguide for the multimode signal against the modal noise

### M. S. Labutina$^1$, A. I. Malekhanov$^{1,2}$, A. V. Smirnov$^2$

Spatial filtering of the multimode signal which is assumed to be a superposition of some regular modes with arbitrary amplitudes and is received against the intensive noise background some part of which is the modal noise. The array filtering performance is chosen to be the array gain. Computer simulation is performed for a vertical array arranged in an ocean waveguide under the conditions of mutually-uncorrelated modal amplitudes for the signal and the modal noise. The focus is comparative study of the optimal array filtering and heuristic technique of matched-mode filtering (with enumeration of the mode numbers). The array gain performance is demonstrated to vary in a wide range of its quantity in dependence on both the modal spectra of the signal and noise and array resolution in mode domain.

Show Abstract## Sound propagation in a shallow water arctic waveguide with an ice cover

## Sound propagation in a shallow water arctic waveguide with an ice cover

### A. A. Lunkov$^{1,2}$, V. G. Petnikov$^1$

Model of the sound channel typical for shallow water seas of the Arctic Ocean is developed. This model includes ice cover roughness and gassy sedimentary layer. Sound field is represented as a sum of coupled modes in the framework of transection approach. Summing is performed over propagating and leaky modes. Thus the model is legitimate even for small ranges from a sound source (~ one waveguide depth) and for low sound speed bottoms (sound speed is less than that in water). Using the developed model, numerical simulations are carried out for sound propagation under ice cover. Ice draft realizations are taken from the database (http://nsidc.org/data/G01360). Results of the numerical simulations demonstrate that the presence of ice cover may cause the increase in transmission loss, that should be taken into account when designing hydroacoustic systems in arctic seas.

Show Abstract## Experimental estimation of statistical characteristics of high-frequency bottom back scattering

## Experimental estimation of statistical characteristics of high-frequency bottom back scattering

### K. P. Lwow, A. A. Fomin

Experimental data was obtained using the Doppler log installed on the boat tacks – North water area of Ladoga lake at depths greater than 100 m. The Gain at the gate of the synchronous receive 4 channels was constant, the ratio s/n >> 1. The obtained coefficients of variation, temporal and spatial correlation. Estimates are compared to traffic conditions with a small velocity and stop the boat. Examines the relationship of ratings with the top layer of the bottom, having in some seas.

Show Abstract## Modeling of acoustic wavefields by means of the random matrix theory

## Modeling of acoustic wavefields by means of the random matrix theory

### D. V. Makarov

A method of acoustic wavefield modeling in a randomly-inhomogeneous underwater sound channel is considered. The method is based on the construction of a propagator in the basis of normal modes of the waveguide. Mode coupling is modeled using random matrices with uncorrelated elements whose variances are determined by inhomogeneity spectrum. Spectral statistics of such propagator is compared with the corresponding data obtained via direct solution of the parabolic equation. It is shown that the propagator constructed via random matrices describes fairly the process of wavefield decoherence with increasing range.

Show Abstract## On the accuracy of measurements of sound pulse arrival angles with vertical antenna

## On the accuracy of measurements of sound pulse arrival angles with vertical antenna

### D. V. Makarov, L. E. Kon'kov

An algorithm for calculation of angular pulse structure in an underwater sound channel is considered. The algorithm is based upon the Husimi transform that allows one to link a wavefield and the corresponding ray arrivals. An important advantage of the algorithm is the possibility of its realization with a relatively short vertical antenna. The notions of fundamental and algorithmic inaccuracies of angular spectrum measurements are introduced. The first one corresponds to fundamental limitations imposed by the uncertainty relation. The second one is related to the antenna’s ability to provide exact calculation of the Husimi transform. We estimate the minimal fundamental inaccuracy for an antenna with length of 300 m.

Show Abstract## Digital solid seismic streamer of a small diameter for the marine engineering seismic exploration

## Digital solid seismic streamer of a small diameter for the marine engineering seismic exploration

### G. A. Maximov, D. M. Denisov, V. A. Larichev, D. N. Lesonen, A. G. Grigor'ev, Z. A. Korolkov

The report presents information about the digital solid streamer of small diameter for the marine engineering seismic exploration developed by N. N. Andreev Acoustic Institute. The developed equipment has been tested in a real commercial project on the shelf of the Kara sea. It has recommended itself as a handy tool during operation and it allowed to obtain the geophysical data of required quality.

Show Abstract## Detection of underwater gas leaks with time reversal acoustic signals

## Detection of underwater gas leaks with time reversal acoustic signals

### Yu. A. Polovinka, A. O. Maksimov

In this report, temporal and spatial focusing properties of time-reversal mirrors are studied for leakage detection. The acoustic remote sensing of subsea gas leakage traditionally uses sonars as active acoustic sensors and hydrophones picking up the sounds generated by a leak as passive sensors. When gas leaks occur underwater, bubbles are produced and emit sound at frequencies intimately related to their sizes. Two factors: the local character of the acoustic emission signal caused by the leakage and a resonant nature of the bubble radiation at their birth make particularly effective use, for active location, time-reversed emission signals in order to obtain a powerful scattering signal. The propagation of emission and time-reversed signals is described in terms of Green’s function of the Pekeris waveguide. This study expands the range of applications that use the mechanism of time-reversal focusing to specific conditions – the vicinity of drilling platforms located on the sea shelf.

Show Abstract## Source localization in a randomly inhomogeneous oceanic waveguide with unknown parameters using adaptive generalized Music algorithm

## Source localization in a randomly inhomogeneous oceanic waveguide with unknown parameters using adaptive generalized Music algorithm

### A. G. Sazontov, I. P. Smirnov

A generalized robust MUSIC algorithm is constructed, that allows to localize an acoustic source under the conditions of incomplete information on a random propagation channel. Under the assumption that the main mechanism causing the sound scattering is a fully-developed wind waves, the results of statistical modeling and experimental testing of the proposed method characterizing its performance in real shallow water are presented.

Show Abstract## Observation of various mechanisms of low-frequency sound scattering on surface waves: the traditional Bragg and new phenomenological scattering models

## Observation of various mechanisms of low-frequency sound scattering on surface waves: the traditional Bragg and new phenomenological scattering models

### M. B. Salin, G. A. Baidakov, O. A. Potapov, B. M. Salin, A. V. Stulenkov, D. D. Razumov

Narrow-band spectra of sound backscattering were investigated in a series of experiments. Two types of scattering spectra are distinguished. In the first case, side-lobes are observed at a certain distance from the carrier frequency. This effect is caused by Bragg scattering on surface waves. In the second case, a smooth broadening of the spectrum around the carrier frequency is observed. In this case, the reverberation spectrum is interpreted using the phenomenological model of sound scattering at subsurface inhomogeneities. These inhomogeneities are moving along circular tracks under the action of wind waves currents, which velocities are rather smaller than the phase velocities of surface waves.

Show Abstract## Acoustic diagnostics of hydrophysical variability on Abkhazian shelf of the Black Sea

## Acoustic diagnostics of hydrophysical variability on Abkhazian shelf of the Black Sea

### A. N. Serebryany$^{1,3}$, G. V. Kenigsberger$^2$, V. P. Elistratov$^2$, K. D. Sabinin$^3$, O. E. Popov$^4$, A. N. Svadkovsky$^3$, L. L. Tarasov$^3$, D. V. Denisov$^3$, E. E. Khimchenko$^1$, V. N. Chekaida$^3$

The results of observation of the variability of marine environment by acoustic and contact methods on the Abkhazian shelf of the Black Sea are presented. Russian-Abkhazian scientific cooperation have been supported by RFBR since 2013. The main goal of the research was to study the dynamics of the coastal waters of the shelf with a steep slope in conditions of spring-summer stratification. Measurements were carried out on a stationary track in the coastal zone by the method of acoustic autogeneration (Furduev's method), but the main part of data was obtained by ADCP «Rio Grande 600 kHz» acoustic Doppler profilometer, which was fixed at trestle. Also, in various sections of shelf were made spatial surveys with ADCP installed on a small motor vessel. Representative data of currents direction in coastal waters, their variability in water bulk and in time, as well as vertical structure of sound velocity and temperature were obtained. The material on temporal and spatial (in vertical) variability of backscattering acoustic signal, which provides information about water contamination, was also obained. Particular attention was paid to the investigation of internal waves, which, in addition to measurements by an acoustic profilometer, were also recorded by anchored vertical thermistor chains. Short-period (from units to tens of minutes) and long-period oscillations of the thermocline with a period close to the inertial one were recorded. The features of internal waves which propagate close to the shore were revealed. Special studies to monitor the coastal currents were conducted in the areas of the Gumista and Kodor rivers flowing into the sea.

Show Abstract## Optimization of the inverse problem algorithms of reconstructing geo acoustic parameters of bottom layers by coherent sounding

## Optimization of the inverse problem algorithms of reconstructing geo acoustic parameters of bottom layers by coherent sounding

### I. P. Smirnov, A. I. Khilko, V. I. kalinina

Methods and algorithms of lay-by-lay reconstruction of geo acoustic parameters of bottom layers with use of parametrical models of formation of the signals reflected from layered semi space at coherent sounding of a bottom of a sea shelf are analyzed. The method of reconstruction, allowing to carryout effective search of the decision in multiple parameter space is offered at restriction of the aprioristic data. By methods of stochastic modeling it is investigated robust algorithms of reconstruction.

Show Abstract## Adaptive integrated network system of high-frequency underwater vision in near to port zones and sea constructions

## Adaptive integrated network system of high-frequency underwater vision in near to port zones and sea constructions

### I. P. Smirnov$^1$, A. A. Khilko$^2$, V. V. Kovalenko$^3$, A. G. Luchinin$^1$, E. A. Mareev$^1$, A. I. Malekhanov$^1$, A. I. Khilko$^1$, V. N. Kravchenko$^4$

For acoustic high-frequency zone vision near to sea constructions it is developed network method based on joint processing of a set of multistatic tomography projections, formed in the underwater channel by vertical radiating and received elements of the modulated pulse signals in the form of the bunches adapted with a waveguide. Efficiency of concrete systems of vision system in real conditions is investigated. Working capacity of a method was investigated in natural experiments.

Show Abstract## Investigation of influence of hydroacoustic fields coherence and on underwater vision efficiency

## Investigation of influence of hydroacoustic fields coherence and on underwater vision efficiency

### A. I. Khilko$^1$, I. P. Smirnov$^1$, A. I. Mashoshin$^2$, A. V. Shafranyuk$^2$

Model of high frequency hydro acoustic fields in randomly inhomogeneous oceanic waveguides is developed. Calculation results of noise sources coherence depending from source and receiver displacement, waveguide characteristics, as well as waveguide random inhomogeneities parameters are presented. Underwater partially coherence vision efficiency is discussed.

Show Abstract## Ray structure of the sound field in a waveguide with a gas-saturated sedimentary layer

## Ray structure of the sound field in a waveguide with a gas-saturated sedimentary layer

### M. V. Yarina$^{1,2}$, A. A. Lunkov$^{1,2}$

Using ray approach analytical expressions for the calculation of sound field complex amplitude in a waveguide, where the bottom is represented as a gas-saturated layer laying on a liquid half-space, are derived. Sound speed in water is assumed to be not depending on depth. Rays are classified by quantity of reflection from upper and lower bounds. Ray branching caused by reflections from the bound between water and gas-saturated layer are considered. Using obtained expressions, the calculations of sound field for the 120-m depth waveguide with various sound speeds in sedimentary layer are carried out. The results of these calculations are compared with the results obtained by ray method for a waveguide with a bottom represented as a liguid half-space with the same parameters as the sedimentary layer. The thickness of gas-saturated layer at which we can neglect the influence of lower half-space is estimated.

Show Abstract## Analysis of robust processing algorithm for sound source bearing estimation

## Analysis of robust processing algorithm for sound source bearing estimation

### V. I. Turchin

Maximum likelihood robust algorithm for tonal source bearing estimation is designed in the presence of smooth field fluctuations on the aperture of linear antenna array; the algorithm is invariant with respect to coefficients determined field distortion. The Cramer-Rao bound is drawn for bearing estimation error variance. It was shown, that the variance depends on coefficient set; some realizations of coefficients can dramatically increase the estimation variance. The numerical examples of robust bearing estimates for "good" and "bad" fluctuations as well as the comparison with the conventional bearing estimates are given. Keywords: underwater acoustics, signal processing, robust algorithms

Show Abstract## Possibilities of Utilizing Linguistic Information in Development of Advanced Speech Signal Compression Technologies

## Possibilities of Utilizing Linguistic Information in Development of Advanced Speech Signal Compression Technologies

### N. V. Bobrov

Speech waveforms are known to be remarkably difficult to compress. Lossless entropy compression methods yield about 30% reduction of the initial waveform size. Delta-compression (and also somewhat similar to it methods based on the ideas suggested by A. Haar and I. Daubechies) allow to improve this result by another 30%. Lossy compression methods yielding much higher compression rates take advantage of the psychoacoustic peculiarities of sound perception by removing certain components of the speech signal that have the smallest effect over its perceived quality, e.g. portions of the spectrum that are “in the shadow” of prominent spectral peaks. It must be observed that all the abovementioned ideas are based on the existence of some a priori knowledge about such kind of data as the speech signal (for instance, that the ordinates of two adjacent points of the speech waveform normally differ by a small value, or that the spectrum of the speech signal usually contains several prominent peaks that determine the perceived quality of the sound). Following this logic, it can be suggested that the a priori knowledge that the speech signal is a container enclosing linguistic data can just as well be used to significantly improve the efficiency of both lossy and lossless compression technologies by including in the data source model the regularities appertaining to the linguistic component of the speech signal. This paper deals with the possible results of this suggestion being tested.

Show Abstract## Acoustic characteristics of vowels from the words of children 14-16 years old

## Acoustic characteristics of vowels from the words of children 14-16 years old

### A. S. Grigorev, E. E. Lyakso

In the study for the first time on the material of the Russian language, acoustic (spectral and temporal) characteristics of stressed vowels from word cut from spontaneous speech of children aged 14-16 years, recognized by auditors with different probability, are described on the basis of the Russian language. Perceptual analysis of children's speech was conducted, aimed at recognizing the meaning of adolescent's words by adults. For words recognized with different probabilities (0.75-1.0 and 0-0.25), the values of the duration of the stressed vowels, the duration of their stationary sections, the pitch frequency value (F0) are described, the values of the formant frequencies (F1, F2). Formant triangles of coordinated vowels for the Russian language (a, y, u) are constructed and their areas are defined.

Show Abstract## Speech communication systems “human–machine” and development of Text-to-Speech algorithms suitable for realization by microprocessors

## Speech communication systems “human–machine” and development of Text-to-Speech algorithms suitable for realization by microprocessors

### R. Potapova$^1$, V. G. Sannikov$^2$, V. V. Potapov$^3$

The systems of artificial intelligence with speech communication elements are usually designed in the assumption that the communication should occur through written words. However, this is not always convenient and, in many cases, quite inefficient. It was found that, for a human user, the most convenient and natural way of communication is realized through speech. By using the spoken language, the user makes less mistakes, becomes less tired, and is capable of a faster response, while the communication rate in this case is considerably higher than in other types of communication (visual, tactile, or tonal).

Show Abstract## Accounting for the effect ofdiffraction divergence and non-ideal reflection from a metal reflector when calibrating a piezoelectric transducer by the self-reciprocity method

## Accounting for the effect ofdiffraction divergence and non-ideal reflection from a metal reflector when calibrating a piezoelectric transducer by the self-reciprocity method

### A. D. Alexandrovna, O. A. Sapozhnikov

One of the methods for calibrating of piezoelectric ultrasonic transducers is the self-reciprocity method. In this approach, a reference acoustic reflector is installed in the medium opposite to the transducer. The transducer is used to emit an ultrasonic pulse and also to receive the corresponding reflected signal (pulse-echo mode). From the comparison of the characteristics of the electrical signal at the stages of radiation and reception, the efficiency of the electroacoustic conversion is found and, thereby, the transducer is calibrated. It is most simple to carry out such calibration in the approximation of plane waves. In practice, however, this condition is violated, which can lead to significant errors. To increase the accuracy of the method, it is necessary to construct a numerical model describing the diffraction divergence of the emitted acoustic beam and the non-ideality of its reflection from the reflector. The construction of such a model is the subject of this work.

Show Abstract## Estimation of potential efficiency of hydroacoustic system

## Estimation of potential efficiency of hydroacoustic system

### M. V. Lebedev

In this work estimation of potential efficiency of hydroacoustic system is obtained. The efficiency criterion is probability of hydroacoustic signal detection with background noise when false alarm probability and target location are known. In the observation model signal and noise are uncorrelated. Covariance of the noise and the signal are known. Analytical formulas for the efficiency criteria for different hydroacoustic system behavior are obtained. In addition, numerical modeling for different detection statistics is given.

Show Abstract## The interrelation between dew point and temperature coefficient of delay of surface acoustic waves in the adsorbed water-lithium niobate system

## The interrelation between dew point and temperature coefficient of delay of surface acoustic waves in the adsorbed water-lithium niobate system

### I. G. Simakov, C. Z. Gulgenov

It was shown that in a humid gas environment at a certain value of the thermal energy (temperature), the temperature coefficient of delay (TCD) of the acoustoelectronic device has a zero value. There is an interrelation between the temperature of zero value of TCD and the dew point. It was suggested that dependence of Zero value of TCD of vapor pressure be used for determination relative humidity. Advantages of this method are considered.

Show Abstract## The use of radiation pressure effect to measure energy losses of an ultrasonic beam during it's passage through an inhomogeneous solid layer placed into the liquid

## The use of radiation pressure effect to measure energy losses of an ultrasonic beam during it's passage through an inhomogeneous solid layer placed into the liquid

### Z. V. Cherepanova, M. A. Kryzhanovsky, S. A. Tsysar, O. A. Sapozhnikov

When an acoustic wave passes through a solid layer located in the liquid, energy losses arise, caused both by absorption in the layer and by reflections from its boundaries. Since a layer inhomogeneous in thickness causes appreciable distortions of the wave front, the traditional method of measuring losses, based on recording the decrease in the amplitude of a plane wave, turns out to be inapplicable. Under these conditions, it is required to measure the wave power by a method that is not sensitive to the amplitude-phase structure of the acoustic field. In this paper, we propose an approach based on measuring the radiation force exerted by an ultrasonic beam on an extended absorber.

Show Abstract## On trends in development of technologies for control of reflected sonar signals

## On trends in development of technologies for control of reflected sonar signals

### V. Yu. Chizhov

Recent developments of sonar technologies for detection of underwater objects call for accurate evaluation of reflection properties. Reflected sonar signals can be determined and measured in two ways: analytically using physical & mathematical models of underwater objects and experimentally. Constraints of full-scale experimental techniques are identified like large size and complexity of structures, difficult experimental procedures. It is argued that the most optimum way is to use scaled models of test object and probing signal.

Show Abstract## Modern technologies and methods for measuring ship’s underwater radiated noise characteristics

## Modern technologies and methods for measuring ship’s underwater radiated noise characteristics

### Yu. F. Shlemov

All countries building ships, in particular submarines, have to persistently address the issues related to measurement and control of ships radiated underwater noise (UN). It is required to meet the environmental (ecological) regulations, but the primary consideration is of course the acoustic stealth of submarines. Analyzing the NATO standards and description of ships UN measurement technologies on ranges in this paper is given a recommendation to improve the Russian standards for use when ships UN measuring and reporting.

Show Abstract## Development of a method for diagnosing the initial stage of material damage by the emitted acoustic field

## Development of a method for diagnosing the initial stage of material damage by the emitted acoustic field

### A. V. Popova

Dynamic loading of structures of responsible use, such as power plant cases, chemical reactors, tanks, pressure vessels, etc., cause the development of damage to materials and structural elements, the initial stage of which is not detected by traditional means of flaw de-tection. As a method supplementing existing methods of defectoscopic control, a contactless remote method for monitoring changes in the spectral characteristics of oscillations of speci-mens and structural elements through changes in the acoustic field emitted by them after local shock effects is proposed. It has been experimentally established that the most structurally sensitive among other spectral characteristics is internal friction, the magnitude of which is mainly due to the energy dissipation in the material. Changes in this characteristic allow to control the initial stages of the process of structural damage to metal, while other characteris-tics retain stable values. The report presents the results of experimental studies on the effect of the level of fa-tigue damage of steel beam samples on the characteristics of the quality factor of the emitted acoustic field, operated under the same conditions, but with different terms. The technique and equipment for testing beam samples for the quality factor of free decaying oscillations with spectral analysis of the acoustic field emitted by them are presented.

Show Abstract## The influence of the liquid with various values of conductivity, viscosity, and permittivity on characteristics of slot wave in acoustic delay line

## The influence of the liquid with various values of conductivity, viscosity, and permittivity on characteristics of slot wave in acoustic delay line

### I. A. Borodina, B. D. Zaitsev, A. A. Teplykh

The influence of the liquids with various values of conductivity, permittivity, and viscosity on characteristics of slot mode in the structure consisting of delay line with shear – horizontal plate wave and upper plate separated by air gap was experimentally studied. Delay line and upper plate were made of Y-X lithium niobate and Z-X lithium niobate, respectively. The excitation of the slot mode leaded to the appearance of the sharp resonant peaks on the frequency dependencies of insertion loss and phase of output signal of delay line. It has been found that the depth and frequency of these peaks depend on pointed properties of liquid contacting with upper plate. The possibility of the identification of liquids with various values of conductivity, permittivity, and viscosity has been demonstrated.

Show Abstract## The sensitivity of dispersion characteristics of acoustic waves in the layered structure "Me/ZnO/Me/diamond" from the thickness of metallic layers

## The sensitivity of dispersion characteristics of acoustic waves in the layered structure "Me/ZnO/Me/diamond" from the thickness of metallic layers

### S. I. Burkov$^1$, O. P. Zolotova$^2$, P. P. Turchin$^1$, I. M. Rychkov$^1$

In the present work, a study of influence of mass loading of two metal layers (upper and lower electrode) on the changes in the phase velocity of the dispersive modes of elastic wave in a piezoelectric layered structure “Me/ZnO/Me/diamond” has been fulfilled. Dependences of this quantity from the h×f product (frequency×thickness of the piezoelectric) and the d/h ratio (metal thickness/piezoelectric thickness) are analyzed. The materials of the metallic layers are aluminum (Al), molybdenum (Mo), platinum (Pt).

Show Abstract## The influence of the electrical boundary conditions near the free side of the piezoelectric resonator with lateral electric field on its characteristics

## The influence of the electrical boundary conditions near the free side of the piezoelectric resonator with lateral electric field on its characteristics

### B. D. Zaitsev, A. M. Shikhabudinov, A. A. Teplykh, I. A. Borodina

The influence of the gap between free side of the piezoelectric resonator with lateral electric field based on lithium niobate and conducting layer on the surface of dielectric plate on the frequencies of parallel and series resonances has been experimentally investigated. The measurements were carried out in the temperature range 14 – 45ºС. It has been shown that the frequency of the parallel resonance monotonically increased on 1.3% at the increase of the gap width from 0 up to 3.5 mm at the fixed temperature. The change in the frequency of the series resonance in the range 0 – 3.5 mm at the constant temperature does not exceed 0.02 – 0.07%. Theoretical analysis numerically confirmed the measured dependencies of resonant frequencies on gap width. It has been shown that the difference between theoretical and experimental dependencies of frequencies of parallel and series resonances on gap width is less than 0.6%. It has been demonstrated the possibility of the development of the meters of displacements with the tempperature compensation which may be used for monitoring the deformations and crack openings of various constructions.

Show Abstract## Development of nanobiosensors based on acoustoelectronic technology

## Development of nanobiosensors based on acoustoelectronic technology

### V. V. Kolesov$^1$, I. E. Kuznetsova$^1$, E. S. Soldatov$^2$, S. A. Dagesyan$^2$, A. E. Melnikov$^2$, V. I. Anisimkin$^1$, V. V. Kashin$^1$

Using methods of acoustoelectronics and integration of nanobiosensors with acoustic delay lines within planar technologies give the chance of development of the acousto-bionanoelectronic sensors with high sensitivity and selectivity. In the paper the acoustoelectric chip sensor based on a lithium niobate plate with thickness 0.35 mm with interdigiral transducer on the surface is developed for excitement of the corresponding acoustic wave. This chip-sensor is inserted into the chip holder with the standard socket of knife type. For production of planar nanostructure of a nanoelectronic transducer the standard photolithography technology, various photoresist, jet ionic etching and a magnetron sputtering was used. The area of 80х80 microns in the center of the chip served for formation of electronic nanostructure which is a prototype of a nanoelectronic transducer. In the obtained nanostructures nanogaps for an immobilization of molecules of proteins-enzymes and creation of selective molecular biosensors can be created.

Show Abstract## Sound transmission through single-layered and multi-layer building enclouseres

## Sound transmission through single-layered and multi-layer building enclouseres

### V. N. Bobylev, V. A. Tishkov, P. A. Grebnev, D. L. Shchegolev, D. V. Monich

The main provisions of the theory of sound matching of wave fields are considered, which makes it possible to investigate the mechanism of sound transmission through single-layer and multi-layer enclosing structures, taking into account the dual nature of sound transmission. Analytical expressions are given for determining the ultimate sound insulation of the fence, which can not be exceeded for a given mass and geometric dimensions. The reserves of increasing of the sound insulation of single-layer and multi-layered enclosing structures used in construction have been investigated.

Show Abstract## To the issue of objective evaluation of combined rooms’ acoustics

## To the issue of objective evaluation of combined rooms’ acoustics

### C. A. Schirjetsky, V. M. Aleshkin, A. O. Subbotkin, V. N. Soukhov

In the article is shown, according to a complex of acoustic measurements, a practical application of method of combined rooms’ reverberation calculation method. Essential usefulness of the method is marked at acoustic designing of combined halls with a transforming barrier between them. Also the results of experimental approval for proposed methods are shown, after acoustic measurements brought by authors in a complex of combined rooms of multifunctional hall and its foyer as a part of the Palace of arts “Neftyanik” in Surgut, Russia.

Show Abstract## Sound insulation with three-layer thin concrete structures with integrated frame

## Sound insulation with three-layer thin concrete structures with integrated frame

### A. Y. Livshits

In a modern high rise residential buildings walls between apartments do not have the necessary soundproofing Rw=23 dB. The reason for this is the use as material for the walls of the lightweight concrete or gypsum blocks. The use of materials with higher density or greater thickness is limited load-bearing capacity of floors and saving living space. To solve this problem developed a three-layer walls consisting of outer layers composed of E or TT shaped concrete blocks, the rotated ribs to each other. Their inner layer is made of sound-absorbing material – mineral wool mats, expanded clay sand. It is experimentally found that the thickness of such structures 160...200 mm provided by sound insulation of structures in 52...53 dB. The article contains the results of research of influence on the sound insulation of three-layered walls such the density of the concrete, the material of the inner layer, and other factors.

Show Abstract## Speech level as a parameter for evaluating classroom acoustics

## Speech level as a parameter for evaluating classroom acoustics

### V. O. Zhukova$^1$, N. G. Kanev$^2$

In this paper we present measured acoustic parameters of BMSTU classrooms of average capacity, designed for holding lectures and seminars. To characterize the classroom acoustics following parameters are selected: the reverberation time, the speech transmission index STI, and the sound level of speech of the lecturer, which is called the speech level in this work. A parameter for characterizing the spatial speech level distribution has been proposed and investigated. The parameter is non-local, therefore the evaluation of acoustic quality by this parameter turns out to be differentiated in long classrooms. A simple method of measurement of speech level in real conditions at different distance from the source is proposed. The relationship of this parameter with other acoustic parameters of classrooms, sizes and internal finishing is analyzed.

Show Abstract## The study of noise level dependence on flow parameters

## The study of noise level dependence on flow parameters

### A. D. Alexandrovna$^{1,2}$, T. V. Zharnikov$^1$

The purpose of this paper is to study the effect of averaged characteristics of the turbulent flow in a pipe on the level of produced noise. The role of noise is played by hydrodynamic pressure fluctuations, increasing with rising Reynolds number, and the average flow velocity is considered as a flow parameter. As a result of the theoretical analysis of the correlation functions of the velocity and pressure fields, the dependence of the noise power on the average velocity was obtained. Numerical modeling of the turbulent flow was performed in a standard CFD package using Large Eddy Simulation (LES) approach. Flows of gas with a density of 100 kg/m3 in the range of Reynolds numbers from 3.2·10^4 to 1.3·10^5 were considered. The analysis of the temporal distribution of pressure and velocity fluctuations showed that they conform with the local isotropic turbulence model in the central part of the flow. The dependence of the noise level on the mean flow velocity was found by calculating the first and the second order moments for fluctuating hydrodynamic quantities. Comparison of the theoretical dependence with the results of numerical simulation showed good agreement.

Show Abstract## Expert system for diagnostics of obesity and functional tone of an organism «BodySonic»

## Expert system for diagnostics of obesity and functional tone of an organism «BodySonic»

### A. G. Kirillov, A. M. Reyman

The results have been presented describing the development of specialized ultrasonic device intended for search and measurements of occurrence depth of strongly reflecting structures in soft tissues (boundaries separating fat and muscle body layers) as well as software forming the expert system for estimation of obesity rate and functional tone of an organism

Show Abstract## Studies of the frequency and temperature dependences of the rate and absorption of ultrasound in modified serum

## Studies of the frequency and temperature dependences of the rate and absorption of ultrasound in modified serum

### A. V. Klemina$^1$, I. Yu. Demin$^1$, V. A. Klemin$^2$, S. N. Gurbatov$^1$

The results of human blood serum studies with the help of the AKB-01 BIOM Acoustic Analyzer enabled the development of non-reagent methods for determining protein and lipid components of blood serum. Further perspectives in this area are related to the use of media obtained from blood serum by affecting the serum of buffer solutions that allow the removal of globulins and leave the albumin in modified serum in the environment of low-molecular components of this serum. Albumin is an important carrier of many components of the human body in the process of its life. The report presents the results of studies of modified serum, the main component of which is albumin. The prospects of using the results obtained for the development of laboratory diagnostic techniques are discussed.

Show Abstract## Human tracheal forced expiratory noises: origin and diagnostic application

## Human tracheal forced expiratory noises: origin and diagnostic application

### V. I. Korenbaum, I. A. Pochekutova, V. V. Malaeva, M. A. Safronova, A. E. Kostiv

Human forced exhallation is accompanied by specific respiratory noise, containing broadband and narrowband components. Acoustic considerations about the origin and characteristics of forced expiratory noises obtained in the last decade are highlighted. The acoustic-biomechanical interrelations of the forced exhallation as well as primary mechanisms and noise production zones are analyzed. The developed acoustic models and empirically revealed phenomena provided to develop a set of acoustic parameters that proved to be promising for functional diagnostics of lung ventilatory function both in general medical practice and in monitoring the human respiratory status under extreme conditions.

Show Abstract## Acoustic tweezer for capturing and moving microparticles based on a focused ultrasonic transducer

## Acoustic tweezer for capturing and moving microparticles based on a focused ultrasonic transducer

### M. V. Lesik, S. I. Solovyov, V. G. Andreev

The problem of trapping and moving microparticles with a single focused transducer at a frequency of 2 MHz is considered. The spatial distribution of the radiation force acting on solid silica particles in the field of a focusing transducer with a focal length of 70 mm and an aperture of 64 mm is calculated. It was shown that there are regions at a distance of 64 mm from the surface of the transducer, where particles with a diameter of 150 μm can be trapped and retained at amplitudes of the vibrational velocity on the transducer surface, exceeding 6 cm/s. Measurements of the displacement of the microparticles in horizontal planes, located at distances of 60-70 mm from the transducer, were carried out. It was shown that the microparticles are moved by the action of radiation force and regions of a clean surface are formed, which sizes and position depend on the distance from the transducer and the ultrasound intensity. The experimental results are corresponded well to the theoretical calculations. The proposed scheme of simple acoustic tweezers can be used in bioengineering for trapping and transport of cells and cellular structures.

Show Abstract## Numerical simulation of the scattering of ultrasonic pulses on surface gas bubbles applied to the problem of ultrasonic imaging of kidney stones in doppler mode

## Numerical simulation of the scattering of ultrasonic pulses on surface gas bubbles applied to the problem of ultrasonic imaging of kidney stones in doppler mode

### A. I. Polyanskiy, O. A. Sapozhnikov

In this work, the features of ultrasonic imaging of kidney stones are considered in conditions when submicron size bubbles are present on the surface of the stones. A model is constructed that makes it possible to observe the so-called twinkling artifact, which consists in the formation of a nonstationary colored mosaic structure in ultrasound examination of stones in the Doppler regime. The model is based on the numerical simulation of the elastic equations and the Nolting-Nepayres equation describing cavitation of bubbles. The results of Doppler signal processing are given, which show that cavitation of bubbles does lead to the appearance of a twinkling artifact.

Show Abstract## Dynamic focusing capabilities of fully populated multielement phased arrays for non-invasive ultrasound surgery applications

## Dynamic focusing capabilities of fully populated multielement phased arrays for non-invasive ultrasound surgery applications

### P. B. Rosnitskiy$^1$, B. A. Vysokanov$^2$, L. R. Gavrilov$^3$, O. A. Sapozhnikov$^1$, V. A. Khokhlova$^1$

New ultrasound surgery applications that are based on the use of multielement phased arrays and high-amplitude nonlinear irradiation regimes require maximum achievable ultrasound intensities at the focus. With the predetermined shape and aperture of the array and intensity at the surface of its elements, the only possibility for increasing focal intensities is a maximally dense packing of the elements at the array surface. In this paper, a prototype of such an ultrasound surgery array with random distribution of elements on its surface has been developed, having the maximum possible (100% without taking into account technological gaps between the elements) density of filling by elements in the form of equal area polygons.

Show Abstract## Acoustic studies of human erythrocytes under the influence of saline solutions

## Acoustic studies of human erythrocytes under the influence of saline solutions

### D. A. Streltsov, A. V. Klemina

Studies of changes in the structure of erythrocytes by an acoustic method-the method of a constant-length interferometer-have been carried out. The method is based on the use of standing ultrasonic waves in a cylindrical resonator. In the course of the experiment, the whole human blood was taken, the erythrocytes of which were hypotonic and hypertonic solutions. The resulting suspension was placed in the acoustic cell of the analyzer. Comparison of the relative velocity of ultrasound in whole blood and after exposure to hypotonic and hypertonic solutions was performed. A clear picture of the change in the structure of erythrocytes under the influence of solutions was obtained, and all the data were obtained by acoustic measurements.

Show Abstract## Ultrasound imaging small scatters through solid-state layer of a nonuniform thickness

## Ultrasound imaging small scatters through solid-state layer of a nonuniform thickness

### D. A. Sukhoruchkin, S. A. Tsysar, O. A. Sapozhnikov

The problem of ultrasound visualization of brain structures is greatly complicated by the presence of the skull, which leads to strong aberrations and attenuation of acoustic waves passing through it. The reason for this is a noticeable difference in sound velocities and acoustic impedances of cranial and soft tissues, as well as heterogeneity of the skull in thickness. In the present paper, in the two-dimensional approximation, a theoretical model is constructed for describing the propagation of acoustic waves in an inhomogeneous medium, including the presence of solid inclusions of the cranial type. On the basis of the obtained data, in the course of a numerical experiment, the possibility of obtaining an ultrasound image of the soft tissues of the brain through a non-uniform thickness solid layer in the application to transcranial diagnostics of brain structures has been analyzed.

Show Abstract## Theoretical research and experimental demonstration of the possibility of creating a plane-wave regime using a large piezoelectric source.

## Theoretical research and experimental demonstration of the possibility of creating a plane-wave regime using a large piezoelectric source.

### M. V. Khasanova$^1$, S. A. Tsysar$^2$, D. A. Nikolaev$^1$, O. A. Sapozhnikov$^1$

The possibility of experimental realization of an acoustic field in the form of a traveling plane wave is studied with the purpose of measuring the absorption coefficient and the speed of sound in a propagation medium. To do so, it is proposed to use a flat piezoelectric source and to perform measurements in the pulsed mode at short distances from the radiating surface. As a result of theoretical modeling based on the exact solution of the wave equation on the axis of a circular piston radiator, spatial and time intervals for the existence of a plane wave mode are revealed. It is shown that the proposed method allows to measure the absorption coefficient of ultrasound in liquids and soft biological tissues in the megahertz frequency range using radiators of centimeter sizes.

Show Abstract## Impulse acoustic microscopy for regenerative medicine material investigation

## Impulse acoustic microscopy for regenerative medicine material investigation

### E. A. Khramtsova$^1$, E. S. Morokov$^1$, T. E. Grigoriev$^{2,3}$, E. A. Gubareva$^4$, A. S. Sotnichenko$^4$, E. V. Kuevda$^4$, V. M. Levin$^1$, Yu. S. Petronyuk$^1$

The aim of this paper is to presents the results of an experimental study of the possibilities of using pulsed acoustic microscopy for noninvasive characterization of materials and tissue engineering objects. The features of visualization by acoustic methods of a non-woven matrix made of thin polysulfone fibers with diameter 4-8 microns as well as a non-woven material based on chitosan with fiber diameter 100-400 nm were studied. To display small-sized cylindrical elements of the structure of matrixes - polymer fibers and strands, collagen fibers of natural tissues, an ultramicroscopic regime based on recording scattered radiation was used. Ultrasonic methods for observing the bulk microstructure of natural extracellular matrix obtained by removing cellular contents from donor organs are proposed. To display the distribution of small-scale structural elements in the cross sections of tissue matrix samples, imaging techniques are developed with the use of dynamic focusing within the object and subsequent halftone mapping of the structure-the B/D (brightness-depth) technique. The results of the research make it possible to characterize the bulk architecture of materials used in regenerative medicine.

Show Abstract## Acceleration of thermal ablation of tissue using shock-wave exposure

## Acceleration of thermal ablation of tissue using shock-wave exposure

### Yu. S. Andriyakhina, I. V. Sinilschikov, M. M. Karzova, P. V. Yuldashev, V. A. Khokhlova

The paper presents a numerical algorithm for simulating the bio -heat equation optimized for calculation the temperature field and generation of volumetric lesions in biological tissue irradiated by high intensity focused ultrasound. Single focus irradiations were studied for three different peak power regimes with the same total energy balanced by the pulse duration: a harmonic regime, typically used in conventional noninvasive ultrasound surgery, and two shock-wave regimes with different peak intensity. The temperature and thermal dose distributions achieved in a single focus over the time between the focus shift of the therapeutic ultrasound array along the irradiation trajectory in tissue were calculated. It was shown that the use of shock-wave irradiations makes it possible to obtain local tissue destruction for heating time on the order of milliseconds.

Show Abstract## Calculation of the Instrument Function of a Broadband Acoustic Thermometric Detector

## Calculation of the Instrument Function of a Broadband Acoustic Thermometric Detector

### A. A. Anosov$^1$, A. A. Sharakshane$^1$, A. D. Mansfeld$^2$, A. G. Sanin$^2$

The instrument function of a broadband (1.6–2.5 MHz) detector that is used in acoustic thermometry has been calculated. Experimental check shown that measured and computed results are in agreement. The effect of the pass band characteristics and the detector’s size on the instrument function has been studied as well as the effect that the instrument function has on an acoustic thermometric signal that is measured by the detector. The ratio of the wavelength (for the mean reception frequency) to the detector’s radius has been shown to be the main parameter that determines the acoustic thermometric signal at distances that are typical of acoustic thermometry. For problems of localizing a heated region, it is optimal to locate the receiver at a distance of 15–25 mm from the region. For example, for a detector 8 mm in diameter, the width of the instrument function at a level of 0.5 of the maximum is 1.2 ± 0.1 mm in this zone.

Show Abstract## Plant for tomographing the acoustic nonlinear parameters with use of coded signals

## Plant for tomographing the acoustic nonlinear parameters with use of coded signals

### K. V. Dmitriev, E. A. Kotelnikov, D. I. Zotov, O. D. Rumyantseva

Tomography schemes based on nonlinear effects of the third order and using two coded and one monochromatic signals or three coded signals as primary ones have been compared. The algorithm of obtaining the tomogram of an acoustic nonlinear scatterer has been adapted for the scheme with three coded primary signals, and the first experiments on the modified plant have been made.

Show Abstract## The interrelation between the acoustic quality factor and the strength of rocks of various types

## The interrelation between the acoustic quality factor and the strength of rocks of various types

### A. S. Voznesenskii, Y. O. Kutkin, M. N. Krasilov

The summary empirical interrelations of dynamic acoustic characteristics of rocks of different genotypes with their strength properties are considered. It is shown that the relation between the acoustic quality factor and the strength can be both monotonic and nonmonotonic. These dependencies can be used for non-destructive evaluation techniques of the rock strength and resources of underground structures.

Show Abstract## Borehole geoacoustic measurements in the system of complex geophysical monitoring and earthquakes forecast in Kamchatka

## Borehole geoacoustic measurements in the system of complex geophysical monitoring and earthquakes forecast in Kamchatka

### V. A. Gavrilov, Yu. Yu. Buss, Yu. V. Morozova, E. V. Poltavtseva

New methods of monitoring of stress-strain states of geological environment have been used for many years in the Petropavlovsk-Kamchatsky testing area. In this paper we estimate the results of using these methods. The data of borehole geoacoustic measurements and electromagnetic measurements with underground electric antennas form the basis of these methods. We analyze the results of the monitoring and compare them with the data of hydrogeochemical and hydrogeodynamic observations to make conclusions about the seismic hazard for Kamchatka region every two weeks. The complex borehole data example shows changes of stress-strain states of geological environment in the zone of the Petropavlovsk-Kamchatsky testing area in time vicinity of the Tohoku megaearthquake (M=9.0, Japan, March 2011) and the strongest Zhupanovsky earthquake (M = 7.2, Kamchatka January 2016).

Show Abstract## Developing the methods and algorithms for solution of inverse acoustical scattering problems

## Developing the methods and algorithms for solution of inverse acoustical scattering problems

### K. V. Dmitriev, D. I. Zotov, O. D. Rumyantseva, S. N. Sergeev, A. S. Shurup

The results of experimental studies of the nature of the propagation of acoustic signals in shallow water are presented, including the case of an ice layer presence. The results of the reconstructing the waveguide parameters and estimating the mode structure of the acoustic field by experimental data in the shelf zone are presented. The possibilities of functional algorithm that is intended for the purposes of tomography of acoustic scatterers represented by refractive-absorbing inhomogeneities and, simultaneously, by a vector field of currents are numerically investigated.

Show Abstract## Development of technology of tomography the earth crust of the shelf and deep sea based on the use of coastal laser strainmeters and broadband low-frequency hydroacoustic emitters

## Development of technology of tomography the earth crust of the shelf and deep sea based on the use of coastal laser strainmeters and broadband low-frequency hydroacoustic emitters

### G. I. Dolgikh$^{1,2}$

Particulars of development of technology the tomography of sea crust on the basis of application of coastal laser strainmeters and low-frequency hydroacoustic emitters are considered. In studying the regularities of distribution of the hydroacoustic signals created by hydroacoustic emitters according to the wedge-shaped shelf of decreasing depth with an assessment of a share of the hydroacoustic energy transformed to seismoacoustic energy, it is established that with depths less than a half of hydroacoustic wave practically the entire signal propagates in the bottom. When carrying out the experimental studies in the Vityaz Bay of the Sea of Japan using coastal laser strainmeters and the hydroacoustic emitter, generating complex phase-manipulated signals with a central frequency of 33 Hz, the foundations of technology of tomography of the earth crust of shelf areas of various seas have been worked out. With the purpose of solving similar problems at large depths of the sea, a powerful low-frequency hydroacoustic emitter on 19-26 Hz was designed and built, designed to generate signals of varying complexity with amplitude up to 10 kPa. During its tests on the shelf of the Sea of Japan, the velocities of the Rayleigh, Stoneley and Love waves were determined on "emitter-laser strainmeter" path.

Show Abstract## Model of inner resonators ensemble to describe of an acoustic noise spectrum by gas flow through porous media

## Model of inner resonators ensemble to describe of an acoustic noise spectrum by gas flow through porous media

### E. A. Ivanova$^{1,2}$, D. N. Mikhailov$^1$

New mathematical model of pore space as a system of coupled Helmholtz resonators was developed. The model allows to improve description of an acoustic noise spectrum, recorded in experiments with gas flow through porous media. An algorithm and code was created for simulation of fundamental frequencies of resonators. The simulation results are presented on the example of the model of Indiana Limestone pore space. The microvortices, appearing in the pores due to inertial effects, are consider as a main mechanism of an acoustic noise generation in the case of the gas flow. Provided numerical simulations (COMSOL Multiphysics) show that the microvortices are formed in the pores at low Reynolds number 1 - 10.

Show Abstract## Development of physical principles of low-frequency acoustic tomography on the Arctic shelf by fiberoptic seismometers

## Development of physical principles of low-frequency acoustic tomography on the Arctic shelf by fiberoptic seismometers

### O. T. Kamenev, Yu. N. Kulchin, Yu. S. Petrov, V. A. Kolchinskiy

The seismometer based on fiber-optic Mach-Zehnder interferometer is proposed and tested. The sensing element of the seismometer is implemented as a multiturn optical fiber coil which allowed to obtain high responsivity to acceleration in the frequency range 1–20 Hz. Stability of the seismometer operation is provided by feed-back control of the interferometer working point. It is experimentally demonstrated that seismometer is able to reliably detect weak seismic vibration with acceleration amplitude at the level of 10^–7 m/s^2.

Show Abstract## Influence of the Rayleigh model parameters of elastic waves attenuation on characteristics of seismographic records and acoustic quality factor of the rock massif

## Influence of the Rayleigh model parameters of elastic waves attenuation on characteristics of seismographic records and acoustic quality factor of the rock massif

### M. N. Krasilov

Computer simulation of elastic waves propagation from explosion source in case of underground mining in a gypsum rock massif for different parameter βdK of Rayleigh model characterizing attenuation, proportional to frequency is carried out. The diagram of dependence of acoustic quality factor versus βdK shows that in case of increase in attenuation acoustic quality factor of a rock massif decreases. βdK change on 2 orders corresponds to change the quality factor of Gypsum rock for 30%. Thus the specified dependence can be used only for qualitative estimate of acoustic quality factor changes of rock massif in time. The quantitative assessment can be made only after necessary adjustments.

Show Abstract## On the properties of the acoustic boundary between a solid and a liquid in the modeling of elastic waves in geo-environments in Comsol Multiphysics

## On the properties of the acoustic boundary between a solid and a liquid in the modeling of elastic waves in geo-environments in Comsol Multiphysics

### V. V. Nabatov

The article describes the specificity of modeling the geophysical monitoring procedures for searching of voids behind subway tunnels lining. In particular, the model requires specific work with boundary conditions on the contact between a solid and a fluid. The obtained simulation results are compared with the results of real measurements in tun-nels. The specific features of the lining responses are revealed.

Show Abstract## On the influence of properties of the liquid saturating geomaterials on the parameters of their thermally stimulated acoustic emission

## On the influence of properties of the liquid saturating geomaterials on the parameters of their thermally stimulated acoustic emission

### E. A. Novikov, M. G. Zaytsev

This paper presents the results of experimental studies of the effect of groundwater salinity on the results of thermoacoustic emission testing of ice wall matrix composed of this water and sandy-clay soil. It has been shown that the impact of this effect on the test results can be reduced. The applicability of thermally stimulated acoustic emission method for the evaluation of strength properties of frozen geomaterial during its thawing and under simultaneous action of mechanical load has been demonstrated.

Show Abstract## Method of passive tomographic reconstruction of ocean bottom deep structures

## Method of passive tomographic reconstruction of ocean bottom deep structures

### D. A. Presnov$^1$, A. L. Sobisevich$^1$, A. S. Shurup$^{1,2}$

In study of the deep structure of the largely inhomogeneous earth's crust methods based on elastic surface waves are effective and increasingly popular. To date, there are a number of similar methods developed originally for use on land. In this paper, an algorithm is discussed for the tomographic reconstruction of the velocity structure of a geological medium in relation to the seabed. As initial data, in this case the surface wave travel time along the interface between the elastic and liquid media is used. The developed method is based on the analysis of noise data recorded by a network of bottom measuring stations. The possibility of estimating the Green's function by calculating the correlation function of seismoacoustic noise is discussed. The method of constructing the velocity map is based on the expansion of the velocity inhomogeneity by the so-called banded basis, originally developed for ocean acoustics problems. As a result, it becomes possible to restore the three-dimensional distribution of the elastic parameters of the seabed. Paper presents the results of experimental data processing performed using the "Plume lithosphere undersea melt" experiment to study the structure of the Hawaiian plume.

Show Abstract## Elastic-anisotropic properties of rocks of different composition and metamorphism facies in the northeast of the Baltic shield

## Elastic-anisotropic properties of rocks of different composition and metamorphism facies in the northeast of the Baltic shield

### O. M. Trishina, F. F. Gorbatsevich, M. V. Kovalevskii

Using the rocks composing the Matert Fm of the Pechenga complex as an example, geological features, metamorphism and physical properties of rocks from the prehnite-pumpellyite to the amphibolite facies were studied. The acoustopolariscopy method was used to evaluate elastic anisotropy, experimental determinations of the density, compression and shear wave velocities under laboratory conditions were made. The mineral composition was used to calculate the density and velocity characteristics for deep conditions of the rock occurrence. The study of rocks of different facies of metamorphism showed that the parameters of physical properties in situ increase from the prehnite-pumpellyite to the amphibolite facies.

Show Abstract## Laboratory study of the acoustic properties of hydrate-bearing sediments

## Laboratory study of the acoustic properties of hydrate-bearing sediments

### G. A. Dugarov$^1$, A. A. Duchkov$^{1,2}$, A. D. Duchkov$^1$, A. N. Drobchik$^1$

A series of laboratory experiments on the formation of hydrate-bearing samples (hydrates of methane and tetrahydrofuran (THF)) and study of their acoustic properties were done. A significant amount of experiments with ice was also performed to compare its properties with gas hydrates. Dependences of the velocities and attenuation of compressional and shear waves on hydrate saturation or initial water saturation (for ice) were obtained. For methane and ice, the most increase of compressional and shear wave velocities is observed in the area of low saturations. This correlates with the attenuation data, quick decrease of attenuation is observed in the area of low saturations for methane and ice. For THF hydrate a gradual increase of compressional and shear wave velocities with increasing hydrate saturation is observed. The differences in the velocity dependences can be explained by the different types of hydrate or ice location in the pore space and requires the use of different models of effective media for their description. For the case of THF hydrate, it is proposed to use the hydrate forming model of a non-cementing type, and for methane hydrate and ice – a cementing type.

Show Abstract## Calculated and experimental study of spatial and temporal characteristics of a cavitation zone

## Calculated and experimental study of spatial and temporal characteristics of a cavitation zone

### E. M. Agrest$^1$, G. N. Kuznetsov$^2$, N. P. Mel’nikov$^3$

The radial and translational motion of single cavitation bubbles interacting with alternating gradients of sound pressure (SP) and among themselves are studied based on analysis of high-speed video data, cavitation noise spectra (CN), and computer modeling. The dynamics of the cavitation field, the physical causes of intense periodic motion for unstable cavities, and the spectral characteristics of CN were studied experimentally and numerically. It was found that, for a given static pressure, development of the cavitation zone is determined by the gas content and viscosity of the fluid.

Show Abstract## Nonlinear evolution of a spherical standing wave in an acoustically excited liquid drop

## Nonlinear evolution of a spherical standing wave in an acoustically excited liquid drop

### E. A. Annenkova$^1$, O. A. Sapozhnikov$^{1,2}$, J. C. Simon$^2$, W. W. Kreider$^2$

When focusing of an intensive ultrasonic beam on liquid-air boundary, a phenomenon called ultrasonic atomization takes place. At moderate levels of ultrasound intensity an acoustic fountain is observed that has the form of a chain of drops, which begin to explode after the fountain is created. The mechanism of these explosions is still unclear. In this work a nonlinear theory of such phenomenon is developed. It is supposed that harmonics of standing waves are formed in a liquid drop because of acoustic nonlinearity, and that process leads further either to pressure amplification at the drop center and formation of a superheated vapor bubble; both effects may be a reason of drop explosion. The theoretical model is based on a quadratic approximation of a wave equation for acoustic pressure in a viscous spherical liquid drop. The solution was taken in the form of a series of harmonics with unknown coefficients. The method of slowly varying amplitudes is applied for further simplification. On the basis of the numerical solution of this problem the wave spectrum in the drop center at different time moments was calculated and the time profile of acoustic pressure in the drop center was predicted; it is strongly distorted with the course of time: at first the sharp section is formed, and then the strong negative and positive peaks appear around it. Observed growth of the negative pressure in the drop center denotes an existence of cavitation in the drop that can be the reason of bubble formation leading further to the drop explosion.

Show Abstract## Excitation of standing waves in viscoelastic resonator under static shear stress

## Excitation of standing waves in viscoelastic resonator under static shear stress

### S. A. Asfandiyarov, T. B. Krit, V. G. Andreev

In this work, we presented the results of the experimental study of standing shear waves in the rectangular parallelepiped shaped resonator made of rubber-like polymer material fixed between two wooden rigid plates. Metal bars were attached to one plate to fix the load mass and create an additional static shear stress in the medium due to the gravity. This tension leaded to a change of elastic characteristics of studied medium which was expressed in the increase of the resonant frequency under stress.

Show Abstract## Acoustic nonlinearity of the upper layer of the sea

## Acoustic nonlinearity of the upper layer of the sea

### V. A. Bulanov

It was studied the distribution of bubbles in sea water theoretically and experimentally, with simultaneous measurements of acoustic nonlinearity and cavitation strength. The studies were conducted in the offshore area of the Sea of Japan with different hydrological and meteorological characteristics. It is shown that the acoustic nonlinearity and cavitation strength of the water containing bubbles in large enough concentrations, exhibit abnormal characteristics that sharply distinguish them from those observed in pure sea water.

Show Abstract## The propagation of intense acoustic beams in a visco-elastic medium with cavities

## The propagation of intense acoustic beams in a visco-elastic medium with cavities

### V. A. Gusev

The propagation of acoustic waves and beams of high intensity in viscoelastic media containing a gas cavity is considered. The response of such medium to the external acoustic impact differs in various frequency-dependent effects and complex temporal dependence, in particular of resonance and relaxation type. The behavior of viscoelastic material in this medium is of a relaxation nature, carrying the memory of the impact in the previous moments of time. The dynamics of internal elements, inclusions and cavities can have a clearly resonant character. The transformation of time profiles and the transverse structure of the beams propagating in such environments with complex internal dynamics is Calculated.

Show Abstract## Study of the interrelationship of the cavitation strength with a variety of sea water parameters

## Study of the interrelationship of the cavitation strength with a variety of sea water parameters

### V. P. Elistratov$^1$, G. N. Kuznetsov$^2$, N. P. Mel’nikov$^3$

Study of the physical dependence and correlation thresholds of cavitation (СTC) measured in various parts of the Atlantic, Indian and Pacific Oceans, with the hydrological, hydro-physical and hydro-chemical characteristics of seawater. Confirmed of the existence of the latitudinal effect (LE) and established increased statistical relationship CTC with the general gas and oxygen content, temperature, and alkalinity. The shown the influence of PVC on areas of divergence and convergence, as well as sea currents.

Show Abstract## Influence of point defects on spatial localisation of nonlinear waves propagating in materials

## Influence of point defects on spatial localisation of nonlinear waves propagating in materials

### V. I. Erofeyev, A. V. Leonteva, A. O. Malhanov

It is shown that the self-consistent mathematical model including the equations of the theory of elasticity and the kinetic equations for density of various types of point defects can be reduced to the nonlinear evolution equation. The equation incorporates the known equations of wave dynamics: the Korteweg–de Vries–Burgers' equation and the Klein–Gordon equation.

Show Abstract## Features of non-linear transformation of the acoustic waves at oblique incidence on a plane boundary between two solids

## Features of non-linear transformation of the acoustic waves at oblique incidence on a plane boundary between two solids

### A. I. Kokshayskiy, N. V. Shirgina, A. I. Korobov

The features of non-linear transformation of longitudinal and shear acoustic waves with vertical polarization (SV-waves) when they fall at the angle of 45o to the plane boundary between two rough environments were studied. Studies were made by the spectral method measuring the generation efficiency of the amplitude of the first, second and third longitudinal and shear acoustic harmonics, reflected and transmitted through a flat interface between two solids, depending on the external pressure applied to the boundary. The amplitudes of the harmonics nonmonotonically depend on the external static pressure applied to the border. The results were in agreement with the analysis indicate the presence of a strong non-linearity of the structure at the boundary between two media due to the mechanisms of contact Hertz and hysteresis non-linearity and can be used in the diagnosis of the quality of the welds.

Show Abstract## The elastic properties of isotropic graphite

## The elastic properties of isotropic graphite

### A. I. Korobov$^1$, V. M. Prokhorov$^2$, N. V. Shirgina$^1$, A. I. Kokshayskiy$^1$

Shear and longitudinal velocities of bulk acoustical waves (BAW) were measured in the samples of isotropic graphite of a rectangular parallelepiped shape. BAW velocity measurements allowed to determine all independent components of the tensor of elasticity of the second order in graphite. In these samples was also investigated acoustoelasticity effect: the experimentally measured dependence of the magnitude of the BAW velocity while uniaxial compression applied to the sample. According to the results of these measurements were identified all independent components of the tensor of the third order elasticity in isotropic graphite by Thurston-Brugger method.

Show Abstract## Theoretical analysis of the radiation force dependence of an acoustic beam on a solid spherical scatterer on the ratio of the beam width to the diameter of the scatterer

## Theoretical analysis of the radiation force dependence of an acoustic beam on a solid spherical scatterer on the ratio of the beam width to the diameter of the scatterer

### A. V. Nikolaeva$^1$, O. A. Sapozhnikov$^{1,2}$, M. R. Bailey$^2$

In this work, the problem of increasing the efficiency of the method of remote displacement of small objects under the action of radiation force is theoretically solved by choosing optimal parameters of an ultrasonic beam. We consider a solid spherical scatterer located in the liquid, irradiated by a focused ultrasonic beam. One of the most important is the question of how the radiation force depends on the ratio between the beamwidth and the diameter of the scatterer. Calculations for a beam with a quasi-Gaussian transverse distribution have shown that the dependence has a clearly pronounced maximum when the transverse dimension of the beam and that of the scatterer are close. A similar result was obtained when using a focusing piston source that is more realistic to the practice. It was hypothesized that the physical cause of this effect is the resonance excitation of shear waves by an acoustic wave propagating along the surface of the stone in water. For verification, force calculations were carried out for two materials: calcium oxalate monohydrate (a material of one type of kidney stones) and gypsum cement U-30. In calculations, the velocity of the longitudinal wave was fixed, and the velocity of the transverse wave varied over a wide range. It turned out that the greatest radiation force was indeed achieved when the velocity of shear waves in the stone was close to the speed of sound in the liquid.

Show Abstract## Nonlinear effects occuring in viscous wave field

## Nonlinear effects occuring in viscous wave field

### A. S. Pavlovskiy, N. G. Semenova

A numerical research on nonlinear time-dependent fields of velocity and pressure in viscous incompressible fluid near an oscillating solid infinitely of the length limited in the direction of oscillation thin plate was performed. The limitation of the plate size along the direction of its oscillation leads to nonlinearity of the problem even when oscillation amplitude of the plate surface is small. The fields of velocity and pressure with big oscillation amplitudes of the plate surface were studied. The explanation of the displacement flows appearance while oscillation of an infinitely thin plate of limited length was given.

Show Abstract## Ultrasonic fountain's flow rate measuring

## Ultrasonic fountain's flow rate measuring

### V. O. Fateev, I. I. Konopatskaya, P. A. Pyatakov, M. A. Mironov

The flow rate (volume velocity) of the acoustic fountain forced by focused transducer, is measured. It is shown that the flow rate is proportional to the acoustic power, radiated by transducer. The coefficient of proportionality is determined.

Show Abstract## Measurement of metal composites moduli by non-contact detection of optoacoustic pulses

## Measurement of metal composites moduli by non-contact detection of optoacoustic pulses

### V. V. Kozhushko$^1$, V. P. Sergienko$^1$, V. N. Myshkovets$^2$

Technology of composite materials is fast developing and promising direction for solution of operational, economic and ecological tasks of substitution of previous generations’ materials. Measurement of the elastic properties of the composites during their development is necessary to confirm that they meet requirements. The paper shows possibilities of measurement of velocities of longitudinal and shear pulses, which are induced by optoacoustic conversion in metallic composites. The feature of suggested approach is non-contact detection of ultrasound by electromagnetic acoustic transducer.

Show Abstract## Acoustic calibration of installation area of antennas using a vector-scalar modules

## Acoustic calibration of installation area of antennas using a vector-scalar modules

### A. I. Belov, G. N. Kuznetsov

Evaluated parameters of the model of the surface layers of soil in a shallow sea. To analyze the mode structure was applied pulses towed pneumatic source and Wigner transform. The seven modes were isolated by vertical vector receivers. Scalar receivers or vector horizontal receivers emit only three modes. It is shown that the use of vertical vector receivers improves the accuracy of estimating the parameters of a layered bottom model.

Show Abstract## The attenuation of sound pressure and orthogonal projection of vector of the vibrational acceleration in shallow water

## The attenuation of sound pressure and orthogonal projection of vector of the vibrational acceleration in shallow water

### A. I. Belov, G. N. Kuznetsov

Studies of the spatial attenuation of the low-frequency vector-scalar sound fields in shallow water performed using a towed pneumo-gun and four-component vector-scalar receivers. Experimental data and calculated on the basis of the acoustic calibration waveguide of laws decay of sound pressure and orthogonal vector projections of the vibrational acceleration showed that the vertical projection of the vector vibrational acceleration decreases significantly faster than the sound pressure field.

Show Abstract## Interference amplitude-phase structure of the narrow-band vector-scalar signals in shallow sea

## Interference amplitude-phase structure of the narrow-band vector-scalar signals in shallow sea

### N. I. Belova, G. N. Kuznetsov

In shallow water is made the comparative analysis of amplitude and phase of low-frequency narrowband vector-scalar signals in areas of interference maxima and minima (IMA and IMI). The essential difference between the interference structure of sound pressure and the horizontal projections of the vector of the vibrational acceleration (speed) from the characteristics of vertical projections are installed. The stability gradients of the phase in the bands of IMA and the rapid phase change in the bands of IMI, presumably related to the dislocation zones are shows.

Show Abstract## Influence of the sizes statistics distribution of bottom discrete inhomogeneous on backscattering of acoustic waves

## Influence of the sizes statistics distribution of bottom discrete inhomogeneous on backscattering of acoustic waves

### I. Yu. Gryaznova, E. N. Ivashchenko, M. S. Labutina

The influence of the distribution of discrete inhomogeneities in size on the average intensity of backscattered acoustic signals is investigated. It is shown that the appearance of scatterers of different sizes on the "translucent" bottom leads to an increase in the average backscattering intensity in comparison with scattering by inhomogeneities of the same size. It is proved, that in the case of a reflecting bottom the contribution of the interference term to the average intensity of backscattering on inhomogeneities of different sizes decreases with increasing mean size of the scatterers.

Show Abstract## About the role of collective effects of scattering in problems of diagnostics of discrete random inhomogeneities

## About the role of collective effects of scattering in problems of diagnostics of discrete random inhomogeneities

### I. Yu. Gryaznova, E. N. Ivashchenko, R. V. Somov

It is proposed the description of the possible correlation of the relative position of discrete bottom inhomogeneities. It is shown that the presence of such correlation results in a significant change in the average backscattering intensity. It is investigated under what conditions the effects arising in the presence of scatter of inhomogeneities in terms of size dominate, and under what conditions the collective effects of scattering dominate.

Show Abstract## An analysis of the applicability of the principle of reciprocity in the vector-scalar fields of multipole sources

## An analysis of the applicability of the principle of reciprocity in the vector-scalar fields of multipole sources

### G. N. Kuznetsov$^1$, A. N. Stepanov$^2$

Investigated the applicability of the principles of reciprocity (PR) in hydroacoustic waveguide for vector-scalar fields (VSF) of multipole sources (MS). It is shown that MS with this principle are divided into two groups: in the first group the fields of sound pressures (SP), horizontal projection of vectors vibrational velocity (HP VVV) satisfy PR, and the vertical projection (VP VVV) of this vectors do not satisfy. In the second group SP and HP VVV principle of reciprocity does not satisfy, and their VP VVV satisfy. Gradients of phase (GP) and the arrival angle in the vertical plane substantially not satisfy PR.

Show Abstract## RADIATION OF A DIPOLE IN A WAVEGUIDE

## RADIATION OF A DIPOLE IN A WAVEGUIDE

### A. D. Lapin

Investigated the sound field of a point dipole with moment in two multimode waveguides – tube with a rectangular and tube with a circular cross-section, the wall of the both tubes are rigid. The field of the dipole obtained by the differentiation of a field monopole on the coordinates this source . It is shown that the approach of the dipole with moment to the rigid wall of the waveguide is lost radiation due to the component of the moment perpendicular to this wall. The calculated radiation power of a dipole in a multimode waveguide, investigated the dependence of this power on the frequency. It is shown that the radiation power of a dipole in a narrow (compared to the wavelength of sound) tube is equal to where is the wave number, and - consequently the density of filling medium and sound velocity in it, - the cross-sectional area of the pipe, - the projection of dipole moment on the axis of the tube.

Show Abstract## Estimation of the accuracy of the numerical description of diffraction effects in highly focused ultrasonic beams using various parabolic models and methods for setting the boundary condition

## Estimation of the accuracy of the numerical description of diffraction effects in highly focused ultrasonic beams using various parabolic models and methods for setting the boundary condition

### I. S. Mezdrokhin$^1$, P. V. Yuldashev$^2$, V. A. Khokhlova$^1$

A numerical algorithm based on the wide-angle parabolic approximation for modeling diffraction effects in strongly focused ultrasound beams is presented. The accuracy of the proposed approach is evaluated and compared with other diffraction approaches: the Rayleigh integral solution; parabolic approximation solution with and without modification of the boundary condition; wide-angle parabolic approximation with different ways of setting a boundary condition.

Show Abstract## Using UltraWide Band signals for Target Strength Measurement of Cylindrical Shell

## Using UltraWide Band signals for Target Strength Measurement of Cylindrical Shell

### Yu. N. Popov, N. M. Lisenkov

A methodology is proposed for target strength measurements by using UltraWide Band (UWB) signals. Using high stability clocks for synchronization of the transmitter and receiver? Accurate time-of-flight measurements can be made between transmitters and receivers via direct and reflected acoustic paths. Target strength is calculated by comparing the correlation of the signals received from the direct path and reflected paths, with reference signals. This technique enables target strength measurements in negative SNR environments. The implementation of this methodology is described.

Show Abstract## Calculation of the non-mirror component of acoustical field from plate with periodical impedance conditions

## Calculation of the non-mirror component of acoustical field from plate with periodical impedance conditions

### Yu. N. Popov, N. M. Lisenkov

The problem of formation is formulated and the calculation algorithm, of non-mirror component with scattering a plane wave on a plate with periodic impedance conditions, is given. The complex scattering could arise, including mirrored component, with the slanting falling of a wave on the flat plate without spatial curvature is shown. The results could be used in vessels design projection and sea constructions projection. The most important issue for them is noise protection.

Show Abstract## Green's functions of the inhomogeneous acoustic layer on an elastic half-space

## Green's functions of the inhomogeneous acoustic layer on an elastic half-space

### v. u. prikhodko

In this paper, we describe a method of constructing functions of a point source of sound waves in inhomogeneous media. The main results obtained for the case of inhomogeneous acoustic layer lying on an inhomogeneous half-space with variable on depth density and speed of sound. Found functional relationships between the characteristics of the sound fields with elastic and spectral characteristics of the inhomogeneous half-space. The study is carried out using the generalized orthogonality relations for the vector of normal waves in stratified envi-ronments. Used the Green formula for the inhomogeneous Helmholtz equation and the formu-las of Betty for the equations of elasticity theory. Keywords: inhomogeneous medium, the ratio of generalized orthogonality, the normal waves, formulas Betty.

Show Abstract## Measurement of sound scattering coefficients in a scale-model rectangular room

## Measurement of sound scattering coefficients in a scale-model rectangular room

### P. A. Trushina$^1$, N. G. Kanev$^2$

Recently proposed method for measuring of sound scattering coefficients in a non-diffuse field is experimentally investigated. Such field can be created in a rectangular room with one absorbing surface. Other surfaces are covered by tested sound scattering elements, which scattering coefficient can be found by means of measured decay curve. Measurements were carried out in the room with dimensions 0.7x0.4x0.4 m at 4-16 kHz. Obtained results have demonstrated the possibility of proposed method for measuring of sound scattering coefficients.

Show Abstract## The behavior of the dispersion curves of quasidipole mode of anisotropic waveguide studied by semianalytical finite element method

## The behavior of the dispersion curves of quasidipole mode of anisotropic waveguide studied by semianalytical finite element method

### T. V. Zharnikov$^1$, D. E. Syresin$^2$, A. A. Nikitin$^3$, A. D. Alexandrovna$^{1,4}$

In this study, repulsion of phase-velocity dispersion curves of quasidipole eigenmodes of waveguides with elliptic cross section in non-axisymmetric anisotropic medium is investigated. The modeling done by the semianalytical finite element technique reveals that in the vicinity of the near-crossover point the dispersion curves repulse rather than cross. The repulsion is accompanied by the rotation of the polarization of two quasidipole modes with frequency. The reason for such a behavior is the lack of symmetry in the model. The crossing is possible only in the models with the exact symmetry. Proposed scenario is important for geophysical problems, because it is the alternative to the well-known stress-induced anisotropy crossing of the dispersion curves.

Show Abstract## Ultrasonic gas flowmeters with laid-on sensors

## Ultrasonic gas flowmeters with laid-on sensors

### A. D. Mansfeld$^1$, A. G. Sanin$^1$, G. P. Volkov$^1$, R. V. Beliaev$^1$, D. V. Moroskin$^2$

Two types of ultrasonic flowmeters with laid-on sensors have been described realizing gas flow measurement through metal pipe wall. The main advantage of developed flowmeters is an ability to measure gas flow without sensor insertion into the wall even at low pressure. Different probing methods (pulse, continuous), "wall" signals influence, useful signal selection methods have been considered. Laboratory and field experimental results are presented.

Show Abstract## Study of the mechanism of auto-unwinding threaded connections with the longitudinal ultrasonic vibrations

## Study of the mechanism of auto-unwinding threaded connections with the longitudinal ultrasonic vibrations

### N. A. Nikolaevich

The mechanism of the vibration auto-unwinding of threaded connections is theoreti-cally and experimentally investigated. It is shown that with the longitudinal vibrations of a rod with the screw heterogeneity the body, placed on the helical surface, undergoes the action of centrifugal force and Coriolis force. As a result of the nonlinearity of the frictional forces of the inertial force they can cause the displacement of body over the helical surface, direction of rotation is determined by the alignment of threaded connection and unit of oscillating me-chanical deformations. The carried out experiments confirmed theoretical conclusions. Direction and angular rate of rotation of body depended on the frequency of the excited longitudinal vibrations of a rod. The obtained results are discussed on the basis of the developed theory.

Show Abstract## Trap and movement of solid particles with use of vortex ultrasonic beam

## Trap and movement of solid particles with use of vortex ultrasonic beam

### V. G. Andreev, M. V. Lesik, S. I. Solovyov

The problem of trapping and moving in a liquid of solid spherical particles by an ultrasonic beam formed by the 8-element antenna array is solved. Requirements are formulated for the configuration of the ultrasonic field and its intensity for trapping and retaining particles of a given radius and density. Measurements of the acoustic power emitted by individual elements of the array are given and it is shown that the amplitude of the vibrational velocity can be sufficient to trap and retain in water the polystyrene particles of submillimeter size.

Show Abstract## Acoustic study of nonlinear viscoelastic properties of liquids

## Acoustic study of nonlinear viscoelastic properties of liquids

### B. B. Badmaev$^1$, T. S. Dembelova$^1$, B. B. Damdinov$^{1,2}$, D. N. Makarova$^1$, E. D. Namdakova$^1$

In this paper we present the experimental results of studying the complex shear modulus and the effective viscosity from the shear strain angle for the example of triethylene glycol using the acoustic resonance method.

Show Abstract## Multi-frequency acoustical method to detect the properties of the turbulent transversal current

## Multi-frequency acoustical method to detect the properties of the turbulent transversal current

### I. B. Esipov$^{1,2}$, V. N. Konovalov$^2$, A. D. Chernousov$^{2,3}$, O. E. Popov$^4$

The results of experimental research the inverse problem to retrieve of the velocity both and spatial position of the turbulent current through the analysis of fluctuation spectra of the acoustical signals of different frequencies. Conditions and accuracy of the inversion by multi-frequency signal, passed on the acoustical path crossed the turbulent current are discussed. The research has been done in echoless chamber with air flow as a turbulent current. In spite of general physics type of this research could be implemented in atmosphere acoustics, aeroacoustics and ocean acoustics

Show Abstract## Ultrasonic control of a condition of the waveguide design

## Ultrasonic control of a condition of the waveguide design

### I. I. Konopatskaya, M. A. Mironov, P. A. Pyatakov

This paper presents the results of experimental studies of feasibility to use a correlation method for monitoring of rod type waveguides under the action of a local compression and heating stress. The possibility of using the method to control the quality of the bolted connection is investigated.

Show Abstract## The experimental investigation of the fast and slow dynamics of the torsional waves in the polycrystalline copper

## The experimental investigation of the fast and slow dynamics of the torsional waves in the polycrystalline copper

### A. I. Korobov, N. I. Odina, E. M. Aseev

The results of an experimental study of the fast and slow dynamics of torsional waves in acoustic resonators made of polycrystalline copper using two methods: resonant (at a frequency of 3 kHz) and pulsed (at a frequency of 138 kHz) are presented. In both cases, as the amplitude was increased, a linear decrease of the velocity of the torsional waves was observed. A comparison with similar results obtained using longitudinal waves was made. For torsional waves, the relative frequency change is approximately 2 times less than for longitudinal waves. As the amplitude of the probing signal is increased, nonlinear absorption of both torsional and longitudinal waves is observed. The observed dependences of the absorption and velocity of torsional waves from the amplitude of the probing signal are explained by the presence in the sample of a structural elastic nonlinearity.

Show Abstract## Distribution of acoustic fields of backward acoustic waves along the thickness of piezoelectric plate

## Distribution of acoustic fields of backward acoustic waves along the thickness of piezoelectric plate

### I. E. Kuznetsova, I. A. Nedospasov

In the paper influence of various electric boundary conditions on distribution of components of mechanical displacement and electric field on plate thickness is investigated. As a result of the carried out researches the possibility of control by the penetration depth and the place of a maximum of shift of the backward waves in XY potassium niobate by use of various types of an electric shortening of a plate has been found. The obtained results can be useful to development of methods of control of shift of particles of the piezoelectric environment at propagation of backward acoustic waves.

Show Abstract## The phase transition from visco-elasticity to plasticity. Description based on the generalized variational principle for dissipative continuum mechanics

## The phase transition from visco-elasticity to plasticity. Description based on the generalized variational principle for dissipative continuum mechanics

### G. A. Maximov

It is shown in the report that the phase transition from the viscoelastic behavior of the medium to the plastic one can be described on the basis of generalized variational principle (GVP) for dissipative continuum mechanics in terms of nonlinear relaxation of internal microrotations of material points. The motion equations derived in the linear approximation on the basis of GVP correspond to the visco-elastic medium, a special case of which is the Maxwell’s medium with a low-frequency behavior as that of a conventional viscous fluid. It is shown how by only choice of the desired functional dependence of the shear nonlinearity it is possible to achieve the transition from the viscoelastic behavior of a medium to its plastic behavior with increasing of shear deformation.

Show Abstract## Study of backward shear waves in piezoelectric plates of crystal class 2mm by asymptotic expansion of the secular equations

## Study of backward shear waves in piezoelectric plates of crystal class 2mm by asymptotic expansion of the secular equations

### I. A. Nedospasov$^1$, V. G. Mozhaev$^2$, I. E. Kuznetsova$^1$

It follows from the expansion of the secular equations near the points of the higher-mode origin that the dispersion relations for waves under study can be represented as a sum of two terms corresponding to two different mechanisms of the appearance of backward waves. One of them is proportional to the curvature of the slowness curve in the vertical direction. The second one is proportional to the negative displacement of the wave rays upon reflection. The competition of these two mechanisms explains and describes quantitatively the spectrum and the existence of the backward shear waves in the X-cut case, or their absence in the Y-cut case in plates of KNbO$_3$ crystals of 2mm class.

Show Abstract## Properties of the inhomogeneous viscous waves excited by a plate of finite size

## Properties of the inhomogeneous viscous waves excited by a plate of finite size

### A. S. Pavlovskiy, S. A. Iiudina, N. G. Semenova

We have numerically solved the set of time-dependent nonlinear equations, which describes motion of an infinitely thin plate oscillating in incompressible viscid fluid. The solution was obtained in the form of oscillation velocity field in the viscid wave. It is a function of the dimensionless length l and the dimensionless oscillation displacement a of the plate. We have plotted trajectories of the fluid particle motion in such a field. It has been shown that they differ from the straight lines normal to the direction of propagation. Such lines are peculiar to the idealized (linear) transverse viscid waves. There appeared a horizontal component of the oscillation speed of the fluid particle. The value of horizontal component depends on a. We have qualitatively analyzed characteristic features of the propagation velocity of viscid wave, excited by a finite plate.

Show Abstract## Estimation of geometrical and acoustical parameters of thin-walled objects using the Lamb waves

## Estimation of geometrical and acoustical parameters of thin-walled objects using the Lamb waves

### D. V. Perov, A. B. Rinkevich, O. V. Nemytova

The algorithm of flaw localization in thin-walled objects, based on the analysis of the dispersive characteristics of Lamb waves, is proposed in this work. It is shown that application of the instantaneous frequency estimation method with the use of wavelet transform makes it possible to reconstruct extensive parts of frequency dependencies of group delay time for different modes of Lamb waves. An additional advantage of proposed method is high noise immunity.

Show Abstract## Variation model of the piezoelectric resonator in the form of a rectangular parallelepiped

## Variation model of the piezoelectric resonator in the form of a rectangular parallelepiped

### A. A. Teplykh, B. D. Zaitsev, A. M. Shikhabudinov, I. A. Borodina

The theory of forced oscillations of the piezoelectric resonator in the form of a rectangular parallelepiped is presented in article. This method based on representation of unknown components of mechanical displacements and electric potential in the resonator in the form of the linear combinations of orthogonal basic functions. The Legendre polynoms was chosed as basic functions for rectangular resonator. The unknown coefficients entering these linear combinations are defined from a condition of a stationarity of the Lagrangian of the system. Unlike the known RPR method (rectangular parallelepiped resonance) which allows to calculate natural frequencies for the free resonator the presented method defines distribution of mechanical and electric fields in the resonator for the given exciting frequency. Advantage of a method is the possibility of use of complex material constants that allows taking into account the viscosity and electrical conductance of material of the resonator.

Show Abstract## Refinement of the material constants of a piezoelectric ceramics of CTS-19 using disk acoustic resonator

## Refinement of the material constants of a piezoelectric ceramics of CTS-19 using disk acoustic resonator

### A. A. Teplykh, B. D. Zaitsev, A. M. Shikhabudinov, I. A. Borodina

In this work the attempt of refinement of the material constants for disk samples of CTS-19 piezoceramics using broadband acoustic spectroscopy method is made. The vector electric impedance of each resonator was measured in a wide frequency range by means of the high-precision LCR measuring instrument. Then the theoretical model of the resonator using a 2-dimensional axisymmetric finite element method was created. Using this model the inverse task was solved with help of an Nelder-Mead algorithm and the refined values of all 10 material constants of a piezoceramics for each sample are calculated. Comparison of the refined values with the values which are earlier published in literature is carried out.

Show Abstract## Theoretical analysis of a torque exerted by the vortex ultrasonic beam on the absorber located in liquid

## Theoretical analysis of a torque exerted by the vortex ultrasonic beam on the absorber located in liquid

### M. E. Terzi, S. A. Tsysar, P. V. Yuldashev, O. A. Sapozhnikov

Waves of any nature carry energy and momentum. In certain configurations of wave beams, angular momentum transfer is also possible: the corresponding beams are called “vortex beams”. In this paper, we study the ability of a vortex acoustic beam of the megahertz range to rotate a large-sized absorber (of several dozen wavelengths in diameter) in a liquid. The vortex beam was formed in water by passing ultrasonic radiation from a focusing piezoceramic source through a non-uniform in thickness 12-sector phase plate made from Plexiglas. The beam propagated vertically upward and was directed to an acoustic absorber in the form of a cylinder 10 cm in diameter and 3 cm in height made of silicone rubber. The absorber was freely suspended on a thin elastic thread. It is demonstrated that when the absorber is irradiated, it is rotated. By scanning the acoustic field in the transverse plane by a miniature hydrophone, two-dimensional distributions of the amplitude and phase of the wave were found, and on the basis of these calculations the moment of the radiation beam force applied to the absorber was calculated. The results of the calculations are in agreement with the observations.

Show Abstract## Vibroacoustics of aircraft with engines of a new generation (Problems and solutions)

## Vibroacoustics of aircraft with engines of a new generation (Problems and solutions)

### V. S. Baklanov

Implementation by new generation aircrafts of future noise standards (Chapter 14 ICAO) for the protection of the environment requires a transition to a high bypass ratio engine of all types of trunk airplanes. The vibration and acoustic spectra of turbofan engines of a high bypass ratio are shifted to the low-frequency part of the sound spectrum. This is caused by a decrease in the rotation speed of the fan rotor and low-frequency components of the disturbing effect of the air-gas engine tract, which will determine the nature of airplane noise and vibroacoustic influence engines on the body and requires a new approach to the development of means for noise and vibration reduction.

Show Abstract## Numerical simulation of the noise of a open rotor

## Numerical simulation of the noise of a open rotor

### I. P. Boychuk$^1$, Yu. I. Rudnyev$^2$

The paper proposes a numerical method for simulating the noise of a open rotor, which allows us to combine a reasonable degree of accuracy in the estimation of aerodynamic noise with an acceptable speed of calculations. This is achieved by applying a simplified scheme for calculating the hydrodynamic problem using the vortex panel method and the simplified Ffowcs Williams-Hawkings method (explicit Farassat formulas) for calculating acoustics. The proposed approach can be used to determine the tonal noise of the rotor. It is characterized by ease of implementation, high speed of calculations, the possibility of taking into account the noise generated by the interaction of the vortex trail coming from the blades of the front rotor, with the blades of the rear rotor. This method is applicable for preliminary noise estimates at the design stage.

Show Abstract## The study of the acoustic impedance of a hole at high sound level

## The study of the acoustic impedance of a hole at high sound level

### A. I. Bykov$^1$, A. I. Komkin$^1$, M. A. Mironov$^2$

The effect of the sound pressure amplitude in the channel on the acoustic impedance of the transverse septum with an aperture is studied. The dependences of the imaginary and real parts of the impedance for different ratios of the hole diameter to the channel diameter in nonlinear modes are obtained.

Show Abstract## Technology for estimation of vibration and sound radiation of marine structures

## Technology for estimation of vibration and sound radiation of marine structures

### E. A. Zavgorodnii

The exact analytical solution obtained by the methods of mathematic physics is suggested for the problems in vibration and acoustic radiation of joined plate systems approximating structures of marine platforms for the analysis of their environment friendliness and habitability. It is theoretically proven that there is a possibility of limited amplitude resonance vibrations of plate parts within plate joints and, therefore, increased acoustic radiation of the system at these frequencies.

Show Abstract## Acoustic and seismic field of movable sources of the noise and vibration

## Acoustic and seismic field of movable sources of the noise and vibration

### Yu. M. Zaslavsky, V. Yu. Zaslavsky, A. M. Sokov

Experimental investigations of natural noise and seismic oscillations induced by motor car quick moving along highway are carried out. The outer acoustic noise and antropogenic seismic signals are recorded by lengthwise microphone array and geophone cable. Fan patterns shown current direction of the movable object are plotted on the basis of electronic scanning of acoustic antenna directivity pattern central lobe. Thin spectral analysis and Doppler frequency shift measurement of discrete component of outer noise spectrum are used for the velocity control. Field pattern is plotted by results of recording on the geophone cable. Prognosis of the object motion direction and velocity is provided due to the wave hodograph lines formed on this field. Wave hodographs are used for checking the data of acoustic record and receiving of informative signs essential for classification also.

Show Abstract## Use of methods of artificial intelligence for assessment of technical condition of the propulsion and steering column (PSC) according to vibration characteristics

## Use of methods of artificial intelligence for assessment of technical condition of the propulsion and steering column (PSC) according to vibration characteristics

### V. V. Makarov

The detailed characteristic of the main sources of the increased vibration in PSC is done. Basic frequencies of sources of vibration of PSC are calculated. By results of stand tests identification of sources of vibration is carried out. By means of neural network methods the algorithm of diagnostics of technical condition of PSC according to vibrational characteristics is developed.

Show Abstract## Features of the spectra of filtration noise in natural and artificial porous media

## Features of the spectra of filtration noise in natural and artificial porous media

### E. A. Marfin$^1$, T. A. Kirpichnikova$^2$, I. S. Metelev$^2$

The filtration of fluids in porous media generates hydrodynamic noise. In the paper, the features of the spectral characteristics of such noises in various samples of porous media have been experimentally investigated. Samples with different values of porosity and permeability were used. The relationship between the characteristic noise frequencies and the filtration properties of porous cores is established. In particular, it is shown that the filtering rate only affects the intensity of the filter noise, while the characteristic frequencies do not change. An increase in the permeability of a porous sample leads to a shift of the main peak in the filter noise spectrum to the high-frequency region.

Show Abstract## Technology for development of vibration and acoustic protection of ship equipment as a combination of experimental and analytical methods

## Technology for development of vibration and acoustic protection of ship equipment as a combination of experimental and analytical methods

### S. V. Popkov

In the development of vibroacoustic protection measures for shipboard equipment it is required to take into account oscillatory energy flows propagating from sources as air-borne noise via supports and non-supporting structures. The paper suggests a list of analytical methods to be used in the development of vibroacoustic protection. Vibroacoustic parameters of equipment and dynamic characteristics of vibroacoustic protection tools that have to be determined experimentally on suitable test facilities are identified.

Show Abstract## Comparative research of efficiency of anti-vibration mittens gloves

## Comparative research of efficiency of anti-vibration mittens gloves

### V. V. Smirnov$^1$, P. Y. Buldakov$^2$, S. N. Buharov$^3$, Yu. N. Viunenko$^4$, E. A. Hlopkov$^2$

The work investigated protective properties of various designs of anti-vibration mittens and gloves. Measurements were taken according to requirements of GOST 12.4.002-97 «Means of protection of hands from vibration. Technical requirements and test methods». The highest protective properties are noted at products with gel materials and the combined anti-vibration elements. Single regularity for all remedies was their low performance in frequency area of a range (8 – 63 Hz). The highest characteristics in this frequency range are noted at mittens "Turbo Donbass", efficiency reached 3-4 dB. Increase in the damping properties of the individual protection equipment (IPE) is reached by the choice of geometrical parameters of elastic details of designs of anti-vibration elements and a combination of materials with various visco-elastic properties.

Show Abstract## Theoretical and practical problems of creation low noise power facilities

## Theoretical and practical problems of creation low noise power facilities

### V. B. Tupov

The permanent operation of power facilities (boilers, thermal power plants, transformer substations and other) is the cause of the excess noise of sanitary norms in the surrounding area. The most ener-gy facilities are located in areas close to residential areas. The theoretical and practical aspects of the creation of a low-noise power facility are discussed. It is shown that the creation of a mathematical model of the energy facility allows us to consider the effect of the limiting factors in the creation of low noise object: the number of noise sources, the noise characteristics of the sources, source loca-tion, operation modes of equipment, index of direction, the orientation of the energy facility in rela-tion to the residential area and the other factors. The location of noise sources at a height above the ground level has a significant impact on noise levels in the surrounding area and the possibility of creation of low noise object. For each type of power facilities were marked groups of noise sources and the typical noise reduction measures were shown. Here are considered well-known and original activities to reduce noise. The important point for the creation of a low-noise power facility is a complex application of noise reduction measures.

Show Abstract## On extreme possibilities of active sound suppression systems monochromatic signals

## On extreme possibilities of active sound suppression systems monochromatic signals

### I. S. Fiks, G. E. Fiks

With regard to the problems of sound insulation devices, radiation which occurs mostly at discrete frequencies, describes a system of active damping (compensation) of sound in outer space. The principle of the system is based on the creation of a system of managed radiators compensating field, inverted relative to the field, the primary source. Compensating field is formed on a monochromatic frequency coinciding or sufficiently close to the frequency compensated signal, which must be known in advance or measured. The efficiency of the system when the signal compensation inaccurately known frequency.

Show Abstract## Роль реактивного элемента в системе шумоглушения авиационного двигателя

## Роль реактивного элемента в системе шумоглушения авиационного двигателя

### Ю. Д. Халецкий, Я. С. Почкин

В качестве глушителей шума авиационных двигателей широко используются сотовые звукопоглощающие конструкции (ЗПК), в последние годы - двухслойные. Разработанная в ЦИАМ конструкция глушителя представляет собой комбинацию традиционных сотовых двухслойных ЗПК и реактивного элемента в виде решетки пластин. Эксперименты показали, что в частотном диапазоне наибольшей чувствительности человеческого уха комбинированный глушитель снижает шум вентилятора на 2-3 дБ больше, чем сотовые двухслойные ЗПК той же длины. Эксперименты были проведены с использованием модели вентилятора авиационного двигателя в качестве источника шума. Другой реализацией реактивного глушителя являются надроторные устройства (НРУ), которые в авиационных двигателях нашли применение в качестве средства повышения газодинамической устойчивости компрессоров. Одной из наиболее успешных конструкций НРУ стала щелевая проставка, устанавливаемая над рабочим колесом. Было исследовано влияние надроторного устройства на шум осевого вентилятора современного авиадвигателя, а также на шум биротативного закапотированного вентилятора. Представлены результаты исследования влияния НРУ на шум модели биротативного закапотированного вентилятора при варьировании конструктивных параметров НРУ.

Show Abstract## On Floquet theory in analysis of vibro-isolation

## On Floquet theory in analysis of vibro-isolation

### A. A. Hvatov

Strong interest to periodic structure acoustical analysis was arisen in second half of 20th century. After classical work by Leon Brillouin a plenty of research has been done. Nevertheless, in periodic structures research area there is lack of mathematically strict papers. In the paper connection between infinite waveguide and its finite part is considered within the frame of several widely used in acoustics differential operators example.

Show Abstract## The evaluation of the effect of supersonic flow on the acoustic field inside the fuselage structures

## The evaluation of the effect of supersonic flow on the acoustic field inside the fuselage structures

### V. E. Khromatov

The paper investigates the impact of aerodynamic pressure for the elasto-acoustic oscillations of cylindrical shells which are in contact with the insulating layer, streamlined a supersonic flow of gas and located in the field of random external forces. Additional aerodynamic pressure measured at the piston theory. There are obtained relations for the spectral densities and dispersion of movement of points of the middle surface of the shell, the dispersion pressure of the acoustic environment.

Show Abstract## Designing of industrial sound protection

## Designing of industrial sound protection

### I. E. Tsukernikov, I. L. Shubin, T. O. Nevenchannaya

The historical inquiry on national normative and technical documents operating since 1977 in the field of designing of protection against industrial noise is given. Substantive provisions and features of the code of rules CP 254.1325800.2016 are considered which was entered into Russia in February, 2017. It is resulted the list of operations and the recommended methods of their performance regulated by the code at designing of protection against the noise created by industrial equipment to meet the noise sanitary regulations at workplaces located in premises and on territory of enterprises and organizations. Rules of performance of acoustic calculations, rules of quiet equipment selection and placing, and also designing of actions for decreases in noise by means of building acoustics are given.

Show Abstract## Measurement and analysis of vibrations caused by the movement of underground trains on surrounding buildings and development of vibration isolation system

## Measurement and analysis of vibrations caused by the movement of underground trains on surrounding buildings and development of vibration isolation system

### V. A. Smirnov, I. E. Tsukernikov

This work presents results of thorough investigations of vibration propagation from underground trains on Kalugsko-Rigskaja line of Moscow Underground. The main aim of the work is to develop effective countermeasures that reduce both the floor vibration and structure-induced noise inside scheduled closely adjacent residential compound. This compound consist from 6 sections, that are located 15 to 52 m from the tunnels. Field investigations were performed to measure the ground velocity during underground train passes both on the ground surface and on the foundations of existing buildings. Transfer functions from ground to building foundation were calculated based on these measurements and the prediction of vibration inside the building was performed. The main steps of the prediction analysis, that is in conversion from the vibration levels of the ground surface to the vibration levels of the floors are: 1) determination of the vibration reduction at the transition from the ground to the foundation of the residential buildings; 2) determination of the vibration transmission losses through the building constructions; 3) determination of the resonant increase of oscillations in the center of the floor compared the oscillation of its contour. The paper presents calculated and averaged over the time of measurements transmission coefficients of vertical vibrations between the said groups of structural elements. The calculated transfer coefficients can be used to predict vibration levels in similar buildings subjected to underground traffic impact. Further analysis allowed for calculation of structural member vibration velocity calculations that were compared to valid sanitary standards. Vibration reduction measurements were proposed and their efficiency calculated.

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