Theoretical Analogies between (Generalized) Lamb and Rayleigh Waves onInsonified, Submerged, Elastic, Hollow and Solid Curved Bodies

摘要

We analyze resonance features in the backscattering cross-sections (BSCS) of anair-filled steel spherical shell submerged in water and insonified by a plane c.w. sound wave. We generalize the concepts of Raleigh (R), whispering gallery (WG), and Lamb waves in half spaces and plates in vacuo to curved solid and hollow bodies immersed in fluids. We study how each shell-wave manifests itself in the various waves in wide bands, and compare Lamb and R/WG waves as the shell becomes a solid sphere to extract their similarities. The fluid-loadings, the shell thickness, and the curvatures of the body generate novel waves in the shell and its BSCS that could have never emerged from earlier models that ignored these effects and which we analyze here.