COMPLEX MULTIPOLE BEAM APPROACH TO ACOUSTIC SCATTERING PROBLEMS

A novel approach to reducing the matrix size associated with the bound ary element/moment method solution of the problem of acoustic scatteri ng from arbitrarily shaped closed bodies is presented in this paper. T he key step in this approach is to represent the scattered field in te rms of a series of beams produced by multipole sources located in a co mplex space. On the scatterer boundary, the fields generated by these multipole sources resemble the Gabor basis functions. By utilizing the properties of the Gabor series, guidelines for selecting the orders a s well as locations of the multipole sources are developed. The presen t approach not only reduces the number of unknowns, but also generates a generalized impedance matrix with a banded structure. The accuracy of the proposed method is verified by using internal accuracy checks a nd by comparing the numerical results with the analytic solutions for spherical scatterers. (C) 1997 Acoustical Society of America.