Acoustic Pulses Scattered by a Rigid Sphere Immersed in a Fluid

Abstract

The scattered field, produced when a plane-wave pressure pulse is incident upon an ideally rigid sphere, is expressed in the terms of classical scattering theory. Using an incident pulse of known spectral content, the resultant scattered pulse is determined, at a number of field points, with a computer. The time-varying forms of the scattered pulses, thus obtained using the completely rigorous classical theory, display characteristics that may be interpreted in terms of circumferential or creeping waves propagating along the periphery of the sphere. The scattered pulse may be conceived as the superposition of a specularly reflected pulse, with a form similar to the incident pulse, and attenuating pulses that travel along the periphery of the sphere from the boundary of the geometrical shadow to the observation point.