Resonance sonar identification of submerged shells that have oscillating internal masses attached by springs

摘要

Abstract: We present a study of the scattering of sound waves by a neutrally buoyant, submerged, spherical shell that has heavy masses internally mounted by springs to the shell. The presence of the attached oscillating masses substantially changes the scattering cross-section of the otherwise empty shell. Furthermore, if the compliance (i.e., the spring constants) of the mounts are varied - all else being the same - then the resulting cross section also varies substantially, often by more than an order of magnitude. It is seen that if the incident plane wave impinges upon the shell at its North pole, where the masses are mounted, then the spring-mass effect on the scattering response is strongest. !13