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Reflection of low-frequency long-range sound in the ocean

100%

Didenkulov I.

Hydroacoustics

2003

tom Vol. 6

117--124

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.

Acoustic vision with the nonlinear techniques

100%

Didenkulov I.

2009

tom Vol. 12

25-38

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.

The difference-frequency acoustic scattering from nonlinear objects

51%

Didenkulov I. , Kustov L. , Martyanov A. , Vyugin P.

2006

tom Vol. 9

31-38

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.

Rotation motion of particles in sound field

51%

Didenkulov I. , Ezersky A. , Selivanovsky D. , Chernov V.

Hydroacoustics

2003

tom Vol. 6

167--170

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.

Bubble motion in an acoustic resonator with flowing liquid

51%

Didenkulov I. , Pronchatov-Rubtsov N. , Tomakov P.

2004

tom Vol. 7

25-30

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.