ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

3aUW5. Acoustic backscatter analysis from a smooth sand surface.

Julia Laughlin

Nicholas P. Chotiros

Appl. Res. Labs., P.O. Box 8029, Austin, TX 78713-8029

A multiscattering theory to describe backscatter behavior in water-filled sands has been developed for smooth sand surfaces. The theory is based on a two-dimensional solution of the diffusion equation and a Biot propagation theory for porous materials. Experiments were conducted at high frequencies (80--120 kHz) to measure backscatter at shallow grazing angles from smooth sand surfaces at varied sand depths. In addition, reflection measurements were made at normal incidence to verify the smoothness of the sand surface. Comparisons of theoretical model backscatter results to experimental measurements were then made. [Work supported by ONR, Ocean Acoustics Program, Code 11250A.]