Coupled Fe (Finite Element) and Hie (Helmholtz Integral Equation) Method for Exterior Acoustics of Axisymmetric Shells

摘要

A conical shell finite element is used to model the shell and the exterior Helmholtz integral equation the fluid, the displacements and pressure being represented by Fourier series expansions in the circumferential coordinate. The dynamic stiffness matrix of the system is obtained by combining the separate dynamic stiffness matrices of the fluid and structure, using 'normal' coordinates alone to save computer time. The excitation is either a time-harmonic point force or a plane wave incident at an oblique angle. In order to validate the problem formulation and computer programs, numerical results of far-field sound radiation from a spherical elastic shell are compared with those from a closed-form shell theory.