Validity study of the distorted wave Born approximation (DWBA) model: Application to the acoustic scattering by marine organisms

Abstract

Applications of the distorted wave Born approximation (DWBA) to the acoustic scattering by weakly scattering marine organisms have shown much progress [Chu et al., J. Acoust. Soc. Am. 93, 2985–2988 (1993); Stanton and Chu, ibid. 103, 236–253 (1998)]. Although the applicability of the model has been examined for simple objects such as spheres, cylinders, and prolate spheroids, the validity of applying the DWBA model to the acoustic scattering by marine organisms with more complicated shapes has not been studied. To evaluate the performance of the DWBA model, a systematic study of the DWBA will be presented. An in-depth study of the 1D problem reveals the fundamental difference between the exact and DWBA solutions and helps us better understand the scattering problem. By studying the internal field of 1D, 2D, and 3D problems for a more general bistatic geometry and evaluating the volume integral derived from the exact Helmholtz–Kirchhoff integral equation, we are able to estimate the validity of the DWBA model in describing the acoustic scattering by arbitrarily shaped marine organisms. [Work supported by NSF and ONR.]