Scattering of sound waves by rotating cylinders and spheres

Abstract

The wave equation for sound waves in uniformly rotating systems is derived. This is applied to the problems of scattering of sound waves by uniformly rotating cylinders and spheres. Rotation introduces an effective modal wave velocity. The boundary conditions are taken as the continuity of pressure and normal displacement. It is shown that scattering exists even if the objects and the external media have the same parameters in their proper frames. For the cylinder problem computational results are given for the scattering amplitude for various angular velocities and angles of incidence. It is shown that the sphere problem is separable only for slow rotation.