Acoustic directivity of rectangular pistons on prolate spheroids

Abstract

The directivity of acoustic radiation from a rectangular piston arbitrarily located on a rigid prolate spheroidal baffle is formulated. The piston is assumed to vibrate with uniform normal velocity and the solution is expressed in terms of a modal series representation in spheroidal eigenfunctions. The prolate spheroidal wave functions are obtained using computer programs that have been recently developed to provide accurate values of the wave functions at high frequencies. Results are presented in the form of far-field polar directivity patterns for various piston/spheroid acoustic sizes, piston locations on the spheroid, and spheroidal shapes.