Reflection and diffraction from prolate spheroids

Abstract

Much theoretical material has been published on acoustic scattering by simple geometries, but in most cases numerical results are limited to asymptotic cases. This paper describes an experimental set-up at Penn State designed to make diffraction measurements in air at frequencies up to 40 kHz, providing for convenient use of models 1–100 wavelengths in dimension. It also presents the results of a study done on the prolate spheroid to determine the sources of reflection and diffraction at various angles of incidence. These results show that a body having two radii of curvature and no surface discontinuities scatters very little energy, and that what is scattered can be attributed soley to “specular” reflection. Examples are shown which demonstrate that, for the range of frequencies used, the results can be accurately predicted by simple geometric calculations.