The modeling of the radiation and response Green’s function of a fluid-loaded cylindrical shell with an external compliant layer

Abstract

Scattering and radiation of acoustic waves from a fluid-loaded cylindrical shell with an external compliant layer are of interest. The compliant layer can be modeled by a normally reacting impedance layer, which has the advantage that complex compliant layer geometries, such as partial compliant layers, can be considered. A question may, however, arise as to the accuracy of this approach. A more rigorous approach is to model the elastic shell and compliant layer using a multilayer shell theory, which has the disadvantage that it cannot be extended to consider partial layers. In this paper scattering results from the normally reacting compliant layer model are compared to those from the multilayer shell model to show that the two approaches produce similar results, except for thickness resonances of the compliant layer. Having established the consistency between the two approaches, results for the far-field acoustic radiation as a function of frequency and radiation angle for a fluid-loaded shell with an external compliant layer excited by an internal ring force are obtained using the normally reacting impedance layer model. These results clearly show the reduction in the far field radiation due to the presence of the compliant layer.

Acoustic radiation of damped cylindrical shell with arbitrary thickness in the fluid field

“…In the field of scattering of the cylindrical shell, Mitri (2006) used the Navier theory to study the scattering of the cylindrical shells by incident plane-progressive waves. Cuschieri (2005) dealt with the similar problem with two methods: the Navier theory and the mass/stiffness impedance equivalence method, and showed that the two approaches produced similar results, except for thickness resonances of the compliant layer. But in the two papers above, the incident wave was assumed as the plane waves, so the problem was simplified to a 2-D plane strain problem.…”