Tonal noise measurements and simulations of an Over-The-Wing propeller

Abstract

The aeroacoustic installation effects of an Over-The-Wing propeller are investigated through experiments and three different simulation techniques with an increasing degree of wing-propeller coupling. The most primitive simulation considers an isolated propeller in the non-uniform inflow imposed by the wing, in which loads are computed by a BEMT formulation with corrections for the unsteady components of lift and drag. Secondly, an iterative chain is developed where the inflow field to the propeller is obtained using a steady-RANS formulation with the inclusion of an actuator disk, combined with a lifting ling formulation. Finally, high-fidelity simulations are performed which make use of an unsteady-RANS formulation, with the propeller advancing in small azimuthal steps. The experiments and simulations show an effective reduction of the first BPF by noise shielding on the pressure side, while the noise increases on the opposite side of the wing. Trends in propulsive and acoustic performance are captured in the simulations, but discrepancies between predicted and measured values are present.