Three-dimensional underwater acoustic scattering from ocean boundaries: Proposed benchmark problems

Abstract

Acoustic scattering from ocean boundaries is a major component of both the signal for mapping sonars and the noise for imaging sonars. However, models of scattering are often reliant on boundary methods such as the evaluation of the Helmholtz-Kirchhoff integral and its approximations. These methods do not account for sub-surface scattering from layers or inclusions although additional approximations are often used. Often, these approximations are employed with only a cursory knowledge of their realm of validity with respect to such parameters as interface roughness conditions, sediment types and layering structure. We propose a series of benchmark problems to begin to establish the regions of validity for extant scattering models. The problems include 3D scattering from an air/water interface, scattering from a layered ocean sediment and scattering from a simple target buried beneath a rough ocean floor. By comparing the results from a variety of benchmark models, it may be possible to establish a better range of validity for the current suite of modeling tools. [Work supported by ONR, Ocean Acoustics.]