Radiation and Scattering by Submerged Elastic Structures

Abstract

Analysis of submerged vibrating structures and of the associated sound fields requires the simultaneous solution of the vibrational and acoustical problems, because surface pressures exerted by a dense medium are typically comparable to inertia and damping forces in metal structures. The scattered field generated by a submerged structure may be similarly altered by the elastic response to the incident wave. This feedback phenomenon, whereby forces exciting the structure must be combined with radiation loading dependent on the structural response, is unimportant in the atmosphere. Consequently, as underwater sound approached airborne sound in practical importance, acousticians were forced to develop new analytical and experimental techniques for studying structure-water interactions. The development of this hybrid branch of acoustics and structural mechanics is reviewed with regard to radiation and scattering. Hunt, even though never personally active in this field, was interested in its applications. He performed his characteristic function of a catalyst by sponsoring theses and encouraging postdoctoral fellows of the Harvard Acoustics Research Laboratory to venture into the novel area of structural acoustics. [Paper prepared under contract with the Office of Naval Research, Acoustics Programs.]