Acoustic scattering in a range-independent, shallow water waveguide with a penetrable bottom

Abstract

At a previous meeting of the Acoustical Society of America, the analysis of the low-frequency, acoustic scattering from an elastic spherical shell in a homogeneous, range-independent waveguide with an impenetrable bottom was presented [G. S. Sammelmann and R. H. Hackman, J. Acoust. Soc. Am. Suppl. 1 79, S76 (1986)]. This previous investigation centered on elucidating the underlying dynamical picture leading to the observed “fine structure” of the scattering resonances of the sphere in the waveguide and to the occurrence of “superresonances.” Here, this analysis was extended to a waveguide with a (liquid) penetrable bottom to more completely explore the dependence of the resonance spectrum of the sphere on the acoustic environment. For a sphere in the sediment layer, the effects of the sediment loading and of the partial “unloading” by the nearby sediment-seawater boundary are discussed. [Work supported, in part, by the Office of Naval Research.]