Boundary integral methods for scattering in non-uniform flows

A two-dimensional boundary element scheme is presented for the prediction of the acoustic field in non-uniform (but irrotational) flow following a Morino coupling approach.1 The scattered field is calculated using a unified aerodynamics and aeroacoustics method where the same boundary integral equation is applied to both aerodynamic and acoustic prediction. These can be posed directly in terms of the velocity potential from which the acoustic field may be derived using Bernoullis equation and the usual small perturbation assumptions. In the present work we examine the case of a two-dimensional body in potential flow in the presence of an acoustic source. Results are presented for the scattering of sound by a 'clean' aerofoil and one with high-lift devices in a mean flow. In both cases, the mean flow and the presence of a wake introduce terms not seen in simpler scattering formulations which assume non-disturbed flow. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.