Noise Generated by Propeller Tip Vortices Interacting with a Wing Leading Edge

Distributed propulsion is a promising concept for future urban air mobility aircraft, enabling lower emissions, higher efficiency, and improved maneuverability. However, aerodynamic interactions between propellers and wings may induce additional noise. Large-eddy simulations for a tractor-configured distributed propulsion system are conducted to gain further insights into the tip-vortex-impingement noise on the wing leading edge. The Ffowcs-Williams and Hawkings method is employed to determine the noise emission to the far field. Comparison of the simulation results with experimental and numerical reference data demonstrates good accuracy of the numerical methods. Results reveal that propeller tip vortices impinging on the wing leading edge generate pressure pulses at the blade-passing frequency. Acoustic footprints are extracted from the hydrodynamic pressure perturbations of the wing near field using a surface-based noise source localization method, which identifies tip-vortex-impingement noise and trailing-edge noise as dominant sources on the installed wing. Although propeller noise remains the primary contributor to overall emissions, propeller–wing interaction leads to a 1–3 dB increase in the noise levels. Both tip-vortex-impingement noise and the trailing-edge noise from the wing exhibit dipole-like directivity, radiating primarily normal to the freestream flow. This study highlights mechanisms and key areas for potential noise mitigation strategies in distributed propulsion systems.