Acoustic scattering in three-dimensional fluid media

The scattering of acoustic waves from three-dimensional compressible fluid scatterers is considered. Particular attention is paid to cases where the scatterers have moderate magnitude in compressibility contrast and nondimensional wave number. The perturbation method based on Pade approximants developed by Chandra and Thompson [J, Acoust. Sec. Am, 92, 1047-1055 (1992)] is extended to allow the solution of problems in three dimensions. It is shown that the functional form afforded by the Pade approximant model allows one to represent and evaluate the characteristic resonances and mode shapes of the scattered pressure field, These modes are a function of the compressibility contrast and the frequency of the incident pressure wave, Numerical results are shown to compare favorably with analytical solutions for scattering from a sphere, The Pade approximant method is shown to be feasible for calculating the pressure scattered from an inhomogeneous distribution of scatterers as well as for determining internal resonance. (C) 1995 Acoustical Society of America.