Numerical Investigation of the Aerodynamic and Aero acoustic Interactions Between a Tractor Propeller and a Lifting Wing

Abstract

The Urban Air Mobility market is currently experiencing rapid growth with significanti nvestments directed toward the development of novel aircraft designs aimed at enhancing performance efficiency and reducing climate impact. Nevertheless, the emergence of noise pollution as a result of aircraft flying closer to previously undisturbed populations is now a pressing concern. Tonal noise, in particular, is widely recognized as the most prevalent and disruptive form of noise pollution. This study proposes a hybrid computational methodology that prioritizes the evaluation of installation effects on a single tractor propeller and wing case, with a specific focus on tonal noise. The hybrid methodology consists of simulating the near-field aerodynamics over the different geometries using an unsteady Reynolds-Averaged Navier-Stokes commercial solver to determine the equivalent sources. Then, the calculation of the acoustic scattering and propagation is handled by a commercial numerical acoustic solver based on the Finite Element Method. This low-order methodology allows discriminating between aerodynamic and acoustic installation effects with moderate computational times. The directivity results indicate that both aerodynamic and acoustic installation effects cause moderate changes in sound level. However, the aerodynamic installation has a greater impacton the directivity, particularly above and below the wing. The noise generated by the unsteady flow over the wing in the propeller-wing geometry is comparable to the levels of propeller noise. However, it radiates in directivity additional to that of the blades, thereby changing the overall directivity and sound level significantly.