An Algorithm to Integrate the Ffowcs Williams-Hawkings Equation on a Rotating, Supersonic Domain

The paper deals with the numerical solution of the FWH equation on a rotating supersonic domain. Based on the emission surface algorithm, the adopted solver performs the integration on the so called acoustic domain in order to avoid the Doppler singularity in the integral kernels. The presence of multiple emission times for the supersonic sources and the particular time evolution of the integration domain force to use a particular data-fitting procedure on both the geometrical and integral quantities. The algorithm may be used in the numerical prediction of the quadrupole source term for helicopter rotors operating at a high transonic regime and in the aeroacoustic analysis of the modern propeller blades, rotating at supersonic speed.