High-intensity focused beam reflection from acoustically soft boundary
High-intensity focused beam reflection from acoustically soft boundary
M. S. Deryabin$^1$, D. A. Kasyanov$^1$, V. V. Kurin$^2$
Nonlinear effects are investigating on high-intensity focused beam reflection from acoustically soft boundary. Experimental setup is used based on Ultrasound Measurement System Control Centre (Precision Acoustics). Fibre-optic Hydrophone System (Precision Acoustics) is applied for acoustic field registration in broad frequency and dynamic range. Radiator Olympus with focal distance 16cm is used for radiating signals with carrier frequency 1MHz. As a model for acoustically soft boundary water – air interface is used. Basic characteristics of focused acoustic beams reflection are studied. It is shown that transformation of wave front in reflected beam is determined by relative position reflected boundary and focal area of focusing radiator. Coincidence reflected boundary and focal plane of focusing radiator gives noticeable increase in acoustic intensity of reflected acoustic beam in comparison with the case of focusing in “infinite medium”.
Show AbstractExperimental investigating on acoustic nonlinear parameters of epoxide compound during polymerization
Experimental investigating on acoustic nonlinear parameters of epoxide compound during polymerization
M. S. Deryabin$^1$, D. A. Kasyanov$^1$, V. V. Kurin
Subject of the article is experimental investigating on nonlinear acoustic characteristics of media situated near percolation threshold associated with change of structure. Epoxide compound during polymerization is presented as a model. Time dependencies of sound velocity, wave attenuation, amplitudes of first, second and third harmonics are experimentally investigating simultaneously. Time dynamics of acoustic harmonics arouse particular interest and show dependence of “nonlinear acoustic portrait” of polymerization process from stage of polymerization, i.e. from structure of substance changing. Some typical aspects can be noted in harmonics behavior of acoustic field propagating into a medium with structural changing under the law of polymerization. Initial stage of polymerization shows amplitudes of first and second harmonics don’t change practically but amplitude of third harmonic increases noticeably. Second stage shows damping increases sharply and amplitudes of harmonics reduce considerably. Than damping becomes small and amplitudes of harmonics reach maximum values in a short time. Parameters of quadratic and cubic nonlinearity show extremum.
Show AbstractExperiment investigating on narrowband intense acoustic noise propagation
Experiment investigating on narrowband intense acoustic noise propagation
M. S. Deryabin$^1$, S. N. Gurbatov$^2$, D. A. Kasyanov$^1$, V. V. Kurin$^2$
Nonlinear effects arising when narrowband noise acoustic beams propagate are experimentally studied. Special experimental setup allows radiating noise acoustic signals with specified characteristics and recording broad frequency range data as the signals propagate. The base of experimental setup is Ultrasound Measurement System Control Centre (Precision Acoustics) with the absolute accuracy positioning no more than 6 microns. Membrane PVDF hydrophone is used for acoustic field registration. The hydrophone is calibrated by manufacturer for frequency range up to 40MHz with non-uniformity no more than 20%. Radiator Olympus with Q factor near 3 is used for radiating noise signals with carrier frequency 2MHz. Typical acoustic pressure level at initial aperture is 1MPa. Experiments show transformation of signal spectrum to universal structure as the signal propagates. The law of spectrum falling in high frequency range is frequency in minus one power.
Show AbstractThe interaction and self-action intense acoustic beams. Theory and experiment
The interaction and self-action intense acoustic beams. Theory and experiment
M. S. Deryabin$^1$, S. N. Gurbatov$^2$, D. A. Kasyanov$^1$, V. V. Kurin$^2$
A series of experiments in the interaction and self-action of intense acoustic wave beams is described. The experimental technique used makes it possible to investigate the propagation of beams at large acoustic Reynolds numbers with high spatial and frequency resolution. The degenerate parametric interaction of intense acoustic beams is considered, the nonlinear amplification of a weak signal on a subharmonic is considered, and the evolution of noise quasimonochromatic beams at large Reynolds numbers is studied.
Show AbstractTheoretical 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 AbstractMethods 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 AbstractResearch 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 AbstractTheoretical 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 AbstractUltrasonic 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 Abstract3D-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.
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