H. Huang G. Gaunaurd
Naval Surface Warfare Ctr., White Oak Detachment, Silver Spring, MD 20903-5640
The scattering of sound waves by a submerged spherical elastic shell coupled to an internal two-degrees-of-freedom mechanical system is studied. The problem is solved using the classical separation-of-variable technique taking into account the effects of the trilateral interaction between the incident wave, the elastic shell, and its internal mechanical system. Numerical results show that echoes from the shell varies significantly with the mechanical properties of the internal system. Particularly, the analytical solution indicates that at the ``fixed base'' resonance frequencies of the internal system, the shell motion stops at the point where the internal system is attached. The scattered acoustic pressure fields at these frequencies are analyzed in detail. [Work supported by NSWC.]