Aeroacoustic analysis of high tip-speed rotating blades

The evaluation of the noise generated by a high tip-speed rotating blade is obtained in time domain through the Ffowcs Williams–Hawkings (FW-H) equation and a numerical procedure developed to model the so-called ‘emission surface’. This procedure, named K-Algorithm, allows us to account for the contribution of the supersonic sources and has been recently improved to reduce the computational effort and to treat some advanced (rotor and propeller) configurations. The method is tested on some complex blade geometries and proves to be robust and effective in predicting both the FW-H linear terms from a supersonic tip speed blade and the quadrupole source terms for a hovering rotor at delocalized operating condition.