Application of computational methods in aeroacoustics

Several applications of a computational code for predicting acoustic scattering effects to problems in aeroacoustics are presented. First, the problem of sound generation by an incident vortical field interacting with an airfoil is considered by examining the analogous problem of the scattering of an incident plane wave by a flat plate. In the second application, the propagation of sound through ducts was examined, where there is an abrupt change in duct cross section. Finally, the scattering of propeller noise by an aircraft was considered, where the propeller noise was simulated by using a distribution of axial and circumferential dipoles. Preliminary predictions showed a significant degree of scattering, qualitatively similar to some wind-tunnel test data.