Calculation of sound scattering using curle's analogy for non-compact bodies

Aeroacoustics is a growing field in aeronautical and automotive industry, mainly through the application of the aeroacoustical analogy. CurIe's analogy is particularly popular in automotive industry. This paper presents some preliminary results of an aeroacoustical study of the sound produced by the leapfrogging of two rectilinear filament vortices within an infinite two-dimensional straight duct. The flow field is obtained from an inviscid kinematic description of the vortical motion. Such incompressible flow description does not contain any acoustical information over the source region. The sound is predicted in frequency domain following two approaches: using a tailored Green's function based on the non-evanescent duct modes, and applying CurIe's analogy to the incompressible flow model. The results show that the pressure field obtained applying CurIe's analogy differ significantly from the pressure field obtained using the tailored Green's function. This is particularly severe at frequencies for which non-planar duct acoustical modes are excited by the vortex motion. The discrepancies are attributed to the lacking acoustical information in the source description. A hybrid method combining CurIe's analogy with a boundary element method to determine a numerical tailored Green's function, is likely to yield a better sound prediction