High-frequency tonal noise prediction for blades in a complex flow environment

This paper presents an innovative technique for computing tonal noise from blade-vortex interaction, contra-rotating rotors and push propellers. This technique is able to predict the noise generated by high-frequency air-loads in a complex aerodynamic environment, due to its computational speed, this technique is applicable to the preliminary design phase and allows to be integrated to a multidisciplinary optimization chain. This technique rewrites the linearized flow equations as the Helmholtz equation and solves it in a Boundary Element Method sense using a three steps procedure where, on each step, the airfoil leading- and trailing edge scattering are accounted for correcting the baseline infinite airfoil. This paper shows the comparison of this technique with the analytical leading edge Amiet Theory and shows its possibility of extension to compute the noise of airfoils with moderate thickness and camber.