Finite Element Modelling of Acoustic Singularities with Application to Near and Far Field Propeller Noise

It is shown that with a suitable structuring of the acoustic field equations, it is possible to include monopoles and dipoles within the same analysis framework as has been extensively used for interior duct acoustics and for duct inlet radiation problems. This allows the extension of the finite element modelling method to include the noise sources in such applications as propellers enclosed in a duct or in free space with mean flows. The necessary structuring of the acoustic field equations is shown, and example calculations are given for the case of one-dimensional sources and body forces in the presence of mean flow, two-dimensional sources, axial body forces, and transverse body forces in the presence of uniform mean flow