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1
Content available Acoustic vision with the nonlinear techniques
Didenkulov I.
Hydroacoustics
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2009
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Vol. 12
25-38
EN
Nonlinear acoustic methods are found increasing applications during the last decades. They are effective for diagnostics of bubbles in liquids and cracks in solids since bubbles and cracks are strongly nonlinear scatterers. In this paper the nonlinear acoustic techniques for imaging of liquids and solids with the nonlinear acoustic defects are described Results of investigation demonstrate possibilities of the nonlinear acoustic techniques in nondestructive testing of different media.
2
Content available The difference-frequency acoustic scattering from nonlinear objects
Didenkulov I., Kustov L., Martyanov A., Vyugin P.
Hydroacoustics
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2006
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Vol. 9
31-38
EN
The difference-frequency acoustic scattering from nonlinear objects such as bubbles was studied for many years and used for bubble diagnostics. In the present paper we consider theoretically two problems. The first one is the difference-frequency scattering from the nonlinear layer in linearly stratified medium. The second problem is the difference frequency scattering from the system of periodic nonlinear layers. In both problems the resonance phenomena are studied and their influence on characteristics of the scattered fields are analyzed. In the third part of the paper we describe experimental method of acoustic difference-frequency vision of large-scale bubbly objects.
3
Content available Rotation motion of small particles in sound field and possible mechanism of sound perception
Didenkulov I., Muyakshin S., Selivanovsky D.
Hydroacoustics
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2005
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Vol. 8
23-30
EN
It is known several mechanisms of perception of sound by hydrobionts. However for simple organisms like small crayfish it is not clear how they can detect sound. One of possibilities is to detect oscillation water motion by microhairs. In this paper it is analyzed a physical mechanism of rotation oscillations of small particles in acoustic field and it application to a problem of sound perception by some hydrobionts.
4
Content available Observation of sonoluminescence and subharmonics
Didenkulov I., Kanakov V., Sanin A., Selivanovsky D., Chernov V.
Hydroacoustics
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2005
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Vol. 8
31-36
EN
In this paper we describe results of experimental investigation of multibubble somoluminescence. Experiments were done in acoustic resonator with water. It was found that sonoluminescence and subharmonics occurrence follows by each other when the amplitude of acoustic pump wave in the resonator increases and decreases. It was also observed a hysteresis effect.
5
Content available Bubble motion in an acoustic resonator with flowing liquid
Didenkulov I., Pronchatov-Rubtsov N., Tomakov P.
Hydroacoustics
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2004
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Vol. 7
25-30
EN
This work describes results of theoretical study of bubble dynamics in an acoustic field. It is known that there is a radiation force on a bubble in an acoustic resonator. This force can provide conditions of bubble levitation. We consider forces acting on a bubble in a resonator with flowing liquid. It is described in the paper bubble motion in such a condition for different parameters. Results of calculations are discussed.
6
Content available Rotation motion of particles in sound field
Didenkulov I., Ezersky A., Selivanovsky D., Chernov V.
Hydroacoustics
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2003
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Vol. 6
167--170
EN
It is known that sound field produces longitudinal oscillation motion of medium. If there are floating particles in a medium those particles oscillate together with liquid. In this paper we consider dynamics of floating particles, which have rotational oscillations in acoustic field. This novel phenomena produces additional sound attenuation due to viscous damping. In the present paper this effect is analytically described. The expression for sound attenuation in suspensions of such particles and estimations of the value of the effect are obtained, and possible applications are discussed.
7
Content available Reflection of low-frequency long-range sound in the ocean
Didenkulov I.
Hydroacoustics
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2003
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Vol. 6
117--124
EN
Experimental results on energetic characteristics of low frequency (about 200 Hz) underwater channel sound reflection by ocean mountains and islands are presented. lt is investigated also sound penetration into shallow water. Transformation of vertical structure of sound field over continental slope is considered. Continental slope and shelf-wedge reflection coefficients of law frequency sound propagating in the underwater waveguide were measured. Results of the work show that low-frequency sound reflections from large-scale bottom irregularities can be important in ocean acoustics.
8
Content available Acoustic tomography of a turbulent water jet
Gavrilenko V., Didenkulov I., Kustov L., Martyanov A., Nechayeva M., Vyugin P., Pronchatov-Rubtsov N.
Hydroacoustics
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2003
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Vol. 6
91--100
EN
Measurement of parameters of flowing liquid is one of problems, which have many applications. in the present paper we describe linear and nonlinear acoustic tomography methods for reconstruction of parameters of a turbulent water jet with gas bubbles. Experiments on both techniques are described. in the linear acoustic method it was measured fluctuations of acoustic signal passed through the jet. In the nonlinear acoustic technique it was measured spectra of combination scattering signals in the jet. Experiments were done in a water tank with a submerged water jet. The results of the work demonstrate the possibility of the tomography of flowing bubble liquids.
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