Scattering of Sound by a Rigid Movable Sphere

Abstract

The echoes from a rigid, freely movable sphere, due to an incident train of plane waves, are computed, together with the associated rigid-body motions of the sphere. These results are compared with those for a rigid, immovable sphere and it is shown that they differ significantly only for values of ka below about 5. The significance of the results in relation to previous work on sonar echoes from solid, elastic spheres in water is discussed. A particular case of forced motion of the rigid sphere, where the echoes diminish to zero at high frequencies, is also investigated.