Coherent Reflection of Acoustic Plane Wave From a Rough Seabed With a Random Sediment Layer Overlying an Elastic Basement
2002
Hsueh, Ping-Chang
This paper studies is considered the problem of coherent re ection of an acoustic planewave from a rough seabed with a randomly inhomogeneous sediment layer overlying auniform elastic basement. The randomness of the sound eld is attributable to the rough-ness of the seabed and the sound-speed perturbation in the sediment layer, resulting in ajoint rough surface and volume scattering problem. An approach based upon perturbationtheory, combined with a derived Green's function for a slab bounded above and below bya uid and an elastic half space, respectively, is employed to obtain an analytic solutionfor the coherent eld in the sediment layer. Furthermore, a boundary perturbation the-ory developed by Kuperman and Schmidt [22] is applied to treat the problem of roughsurface scattering. A linear system is then established to facilitate the computation of thecoherent re ection eld. The coherent re ection coe cients for various surface roughness,sediment randomness, frequency, sediment thickness, and basement elasticity have beengenerated numerically and analyzed. It was found that the higher/larger size of surfaceand/or medium randomness, frequency, thickness, and shear-wave speed, the lower thecoherent re ection. Physical interpretations of the various results are provided.
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