A Boundary Integral Formulation for Sound Scattered by Elastic Moving Bodies

This paper deals with the acoustic field scattered by elastic bodies in motion. Starting from the Ffowcs Williams and Hawkings equation for porous surfaces, a boundary integral formulation for the acoustic disturbance is derived. For moving, vibrating bodies impinged by acoustic waves it yields a unified approach for the determination of surface pressure perturbations and sound radiation. The scattered field is determined from the knowledge of the impinging pressure, without requiring the evaluation of its normal derivative over the surface of the scatterer. A boundary element method is applied for the numerical solution of the integral formulation. The resulting prediction tool is validated through acoustic analysis of stationary rigid and elastic spherical shells, as well as a wing and a vibrating sphere in uniform motion. The advantages of the proposed sound scattering formulation are discussed.