2pUW2. Acoustic scattering by a partially buried three-dimensional elastic object.

Session: Tuesday Afternoon, May 14

Time: 1:35

Author: Raymond Lim
Location: Coastal Systems Station, Code 130B, Panama City, FL 32407


A formally exact transition-matrix solution for the spectral scattering response of an elastic object that penetrates a plane-stratified fluid host is formulated. The field scattered from the segment in each layer is expanded in a global outgoing basis centered on that segment and these segment fields are superimposed at the field point. A manageable structure for the transition matrix is maintained by using the boundary conditions to couple these segment fields to the interior field of the object via a single exterior surface field expansion centered on the origin of the object. The standard set of regular spherical eigenfunctions of the Helmholtz equation are used to expand the exterior surface field. Numerical tests for an axisymmetric spheroid indicate this choice yields a viable solution but convergence is better for flattened shapes (oblate) than elongated shapes (prolate). Examples are presented to illustrate environmental effects on the backscatter by a bubble and an elastic spheroid that penetrate a water/sediment interface. [Work supported by ONR.]

from ASA 131st Meeting, Indianapolis, May 1996