Influence of Internal Wave on the Sound Propagation in the Subsurface Bubble Layer

2011 ◽  
Vol 8 (1) ◽  
pp. 54-64
Author(s):  
R. Grimshaw ◽  
L.A. Ostrovsky ◽  
A.S. Topolnikov ◽  
K.R. Khusnutdinova
Keyword(s):  
Internal Wave ◽  
Speed Of Sound ◽  
Acoustic Signal ◽  
Sound Propagation ◽  
Japan Sea ◽  
Subsurface Ocean ◽  
Ocean Layer ◽  
Bubble Layer ◽  
Linear Internal Wave ◽  
Local Speed

In the paper the influence of non-linear internal wave on the propagation of acoustic signal in the subsurface ocean layer containing gas bubbles is considered. During interaction with surface waves the internal wave causes its collapse and influences the structure of bubble layer. Inhomogeneous structure of the layer promotes the local speed of sound and intensity of scattering near the ocean surface to modulate by internal wave with slight shift in phase in the direction of its propagation, which agree with recent experimental observations made on the shelf of Japan Sea.

INTEGRAL EQUATION COUPLED MODE APPROACH APPLIED TO INTERNAL WAVE PROBLEMS

2001 ◽  
Vol 09 (01) ◽  
pp. 149-167 ◽  
Author(s):  
D. P. KNOBLES ◽  
S. A. STOTTS ◽  
R. A. KOCH ◽  
T. UDAGAWA
Keyword(s):  
Integral Equation ◽  
Internal Wave ◽  
Integral Equations ◽  
Sound Propagation ◽  
Integral Equation Method ◽  
Coupled Equations ◽  
Coupled Mode ◽  
Energy Conserving ◽  
Linear Internal Wave ◽  
Wave Problems

A two-way coupled mode approach based on an integral equation formalism is applied to sound propagation through internal wave fields defined at the 1999 Shallow Water Acoustics Modeling Workshop. Solutions of the coupled equations are obtained using a powerful approach originally introduced in nuclear theory and also used to solve simple nonseparable problems in underwater acoustics. The basic integral equations are slightly modified to permit a Lanczos expansion to form a solution. The solution of the original set of integral equations is then easily recovered from the solution of the modified equations. Two important aspects of the integral equation method are revealed. First, the Lanczos expansion converges faster than a Born expansion of the original integral equations. Second, even when the Born expansion diverges due to strong mode coupling, the Lanczos expansion converges. It is shown that the internal wave problems examined are essentially one-way propagation problems because one observes good agreement between the coupled mode solutions and those provided by an energy-conserving parabolic equation algorithm. In the Workshop examples, at both 25 and 250 Hz, significantly greater coupling between modes occurs in the linear internal wave field case than the nonlinear soliton case.

Sound Propagation through an Underwater Bubble Layer with Transition Sublayers

1996 ◽  
Author(s):  
S. W. Yoon ◽  
B. K. Choi ◽  
A. M. Sutin ◽  
I. N. Didenkulov
Keyword(s):  
Sound Propagation ◽  
Bubble Layer

The diffraction of blast. II

1950 ◽  
Vol 200 (1063) ◽  
pp. 554-565 ◽  
Keyword(s):  
Solid Surface ◽  
Speed Of Sound ◽  
Uniform Flow ◽  
Incident Shock ◽  
Plane Shock ◽  
Angle Of Incidence ◽  
Straight Segment ◽  
Reflected Shock ◽  
Perpendicular Distance ◽  
Local Speed

The head-on encounter of a plane shock, of any strength, with a solid corner of angle π - δ is investigated mathematically, when δ is small, by a method similar to that of part I. The incident shock is found to be reflected from each face as a straight segment, the two segments being joined by a shorter curved portion. Behind each straight segment is a region of uniform flow, the two regions being joined by one of non-uniform flow, bounded by arcs of a circle with centre at the corner, which expands at the local speed of sound, and by the shock, which is curved only where intersected by the said circle. The pressure is approximately equal in the two regions of uniform flow, but is less in the region of non-uniform flow between them; and it is found that if the deficiency of pressure therein, divided by the angle δ and by the excess of pressure behind the reflected shock over that of the atmosphere, be plotted at points along the solid surface, after the incident shock has travelled a given perpendicular distance beyond the corner, then the curve is independent of δ and of the precise angle of incidence of the shock, and changes remarkably little in the whole range of incident shock strengths from 0 to ∞ (see figures 5 to 8). It is suggested that some of the above qualitative conclusions may be true even if δ is not small. The case δ<0, when the corner is concave to the atmosphere, is also considered. Shock patterns are found in cases when the incident shock has already been reflected from one, or both, walls before reaching the corner (figures 9 to 11).

scholarly journals Photoacoustic–ultrasonic dual-mode microscopy with local speed-of-sound estimation

2020 ◽  
Vol 45 (14) ◽  
pp. 3840
Author(s):  
Wentian Chen ◽  
Chao Tao ◽  
Nghia Q. Nguyen ◽  
Richard W. Prager ◽  
Xiaojun Liu
Keyword(s):  
Speed Of Sound ◽  
Dual Mode ◽  
Local Speed
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