Fast transient analysis of acoustic wave scattering from rigid bodies using a two-level plane wave time domain algorithm

It is well known that the computational cost associated with the applicatio n of classical time domain integral equation methods to the analysis of sca ttering from acoustical targets scales unfavorably with problem size. Indee d, performing a three-dimensional Scattering analysis using these methods r equires O(NtNs2) operations, where N-s denotes the number of basis function s that model the spatial field distribution over the surface of the scatter er and N-t is the number of time steps in the analysis. Recently, novel pla ne wave time domain algorithms that augment these classical methods and the reby reduce their high computational cost have been introduced. This paper describes such a plane wave time domain algorithm within the context of the analysis of acoustic scattering from rigid bodies and outlines its incorpo ration imo a time domain integral equation solver ill a two-level setting. It is shown that the resulting scheme has a computational complexity of O(N tNs1.5 log N-s). Examples comparing the accuracy and computational efficien cy of the conventional and accelerated methods are presented. The proposed two-level scheme renders feasible the broadband analysis of scattering from large and complex bodies. (C) 1999 Acoustical Society of America. [S0001-4 966(99)02911-2].