Aeroacoustic Analysis of a Wing-Tip Mounted Propeller Configuration

In this work, the turbulent flow field around a wing-tip mounted propeller configuration is simulated using the model and test conditions released by the Workshop for Integrated Propeller Prediction (WIPP). In particular, the unsteady Reynolds-averaged Navier-Stokes and enhanced delayed detached eddy simulations with Spalart-Allmaras turbulence model are performed in a time-accurate manner with the multi-zone sliding mesh technique in which the propeller is allowed to rotate while the wing and the nacelle remain stationary. Time-averaged pressure coefficients at four spanwise locations along the wing surface are shown to be in good agreement with the experimental data, including the two locations directly in the propeller slipstream. The simulations on reveal two major noise sources of this wing-tip mounted propeller configuration, namely the turbulent wake and tip vortex generated by the propeller blades, both impinging upon the wing and nacelle surfaces as they convect downstream. Visualization of the surface pressure fluctuations reveals the noise footprints on this integrated propeller-wing system. In particular, the impingement of propeller blade tip vortices on the leading edge of the wing immediately below the nacelle is identified to be the dominant noise source. This is confirmed by the farfield noise computation for observers located on the azimuthal propeller plane and the fly-over plane, which reveals that at most observer angles, especially the side-line ones, the unsteady loading on the wing and nacelle surfaces represents the dominant noise source.