Hybrid ray-mode parametrization of acoustic scattering from submerged thin elastic shells with interior loading

Abstract

A phenomenologically based hybrid ray-mode synthesis strategy is applied here to reconstruct the backscattered field from a submerged thin cylindrical elastic shell with internal structural loadings, which is insonified by a normally incident time-harmonic plane wave. The strategy is based on the Kirchhoff formulation for the acoustic field which expresses the scattered pressure explicitly in terms of the empty-shell Green’s function augmented by on-surface forces and bending moments that account for the internal effects. Earlier studies have shown that the prominent observable features in the scattered far field may be attributed to waves on the shell and resonant modes associated with the internal system. Accordingly, a ray formulation is utilized for the empty-shell Green’s function, while an angular harmonic (resonant mode) solution is used for the coupling forces and bending moments. This hybrid scheme is shown to reconstruct previously derived harmonic series solutions accurately and efficiently in the intermediate and high-frequency domains.