On the possibility of singularities in the acoustic field of supersonic sources when BEM is applied to a wave equation

Using a time domain method based on the Ffowcs Williams-Hawkings equation, a reliable explanation is provided for the origin of singularities observed in the numerical prediction of supersonic propeller noise. In the last few years Tarn and, more recently, Amiet have analyzed the phenomenon from different points of view. The method proposed here offers a clear interpretation of the singularities based on a new description of sources, relating to the behaviour of lines where the propeller blade surface exhibits slope discontinuity.