Acoustic Scattering Performance for Sources in Arbitrary Motion

In this paper, an analytical time domain formulation based on Ffowcs Williams-Hawkings (FW-H) equation is derived for the prediction of the acoustic velocity field generated by moving bodies. This provides the imposition of the Neumann boundary condition on a rigid scattering surface. In order to calculate the scattering sound pressure of the duct, a thin-body boundary element method (BEM) has been proposed. The radiate sound pressure is calculated using the acoustic analogy FW-H equation. The scattering effect of the duct wall on the propagation of the sound wave is presented using the thin-body BEM. Computational results for a pulsating sphere, dipole source, and a tail rotor verify the method. The sound pressure directivity and scattering effect are shown to demonstrate the applicability and validity of the approach.