Numerical and Flow Sensitivity Study of Propeller and Wing Interaction Noise

Abstract

High-fidelity simulations are used to enhance the understanding of the sensitivity of propeller-wing interactions across a spectrum of conditions, focusing on both aerodynamics and aeroacoustics. The aerodynamics is analyzed using high-fidelity computational fluid dynamics, while the acoustics is assessed through the application of impermeable Ffowcs Williams and Hawkings surfaces. Initial assessments concentrate on the influence of simulation parameters on both convergence and accuracy of numerical results. It is determined that reducing the wake grid spacing from 10% of the reference chord length to 7.5% offers no notable improvement to acoustic predictions. Moreover, comparisons between acoustic predictions employing the SST turbulence model and the SA model, with and without transition modeling, reveals differences that are minor in comparison to the prediction errors observed against experimental data. Then, the sensitivities of both aerodynamic and aeroacoustic responses are examined in relation to freestream and tip Mach numbers, angle of attack, and side slip angle. Aerodynamic analyses highlight a strong dependency of both steady and unsteady propeller loading on freestream and tip Mach numbers, and the wing angle of attack. The wing steady loading demonstrates sensitivity primarily to freestream Mach number and the wing angle of attack, whereas the unsteady wing loading is influenced by freestream and tip Mach numbers, and the angles of attack of both the propeller and the wing. The introduction of a side slip angle is found to alter propeller and wing interactions significantly, leading to an increase in propeller thrust. Aeroacoustic investigations show that the sound pressure level of the first blade passing frequency of the propeller rises with tip Mach number but decreases as the freestream Mach number increases. Wing noise exhibits increased sensitivity to tip Mach number with rising freestream Mach number. However, due to phasing, it is not always possible to distinctly separate trends in total noise from the underlying physical mechanisms such as the destructive interference occurring between propeller and wing noise signals. Additionally, the side slip angle is found to amplify the propeller, wing, and the system noise as a whole.