COMPRESSIBLE AERODYNAMICS OF ROTATING BLADES BASED ON AN ACOUSTIC FORMULATION.

In this report, an acoustic formula derived by Farassat for the calculation of the noise of moving bodies is applied to aerodynamic problems. Farassat's acoustic formulation is a time domain result suitable for slender wings and bodies moving at subsonic speeds. The main contribution of this report is the derivation of a singular integral equation in terms of the surface pressure which must then be solved numerically for aerodynamic purposes. However, as the 'observer' is moved onto the body surface, the divergent integrals in the acoustic formulation are semiconvergent. The procedure for regularization (or taking principal values of divergent integrals) is explained, and some numerical examples for ellipsoids, wings, and lifting rotors are presented.