Boundary element formulations for structural acoustics including mean flow effects

A Boundary Element Method (BEM) is developed for application to general problems of structural acoustics. An integral formulation is first developed for the fluid domain, which is idealized as a linear acoustical medium with a piecewise constant mean flow field. As a result, this formulation permits approximate solution of problems involving relative motion between a structure and the fluid. However, in the limiting case of zero mean flow, the standard Helmholtz representation obtains. Meanwhile, the structure is assumed to respond as a linear elastic solid, and is also represented via a BEM approach. The numerical implementation utilizes state-of-the-art boundary element technology, including adaptive integration schemes that combine analytical and numerical algorithms. Three-dimensional, two-dimensional, and axisymmetric time-harmonic problems are addressed, and several numerical applications are included to demonstrate the validity and accuracy of the present approach, even when applied to thin-walled structures.