Acoustic scattering from a sphere of small radius coated by a penetrable one

The scattering of a plane acoustic wave from an impenetrable or a penetrable sphere of acoustically small radius coated by another penetrable sphere, is considered in this work. The method of separation of variables is used, combined with translational addition theorems for spherical wave functions. Analytical expressions are obtained for the scattered pressure field and the various scattering cross sections. Numerical results are given for various values of the parameters and for both an impenetrable or a penetrable inner sphere. (C) 1995 Acoustical Society of America.