Aeroacoustic and Aerodynamic Investigation of a Lifting Propeller Interacting with a Wing in Take-Off Configuration

Urban air mobility has recently gained popularity, driving the demand for propeller driven vehicles. Particularly, electrical vertical take-off and landing vehicles have received attention due to their operational capability (e.g., minimal space for takeoff and landing, high cruise efficiency, and sustainability). This study presents an experimental investigation of an installed lifting propeller interacting with a NACA~0012 wing, varying the horizontal offset and vertical height between the wing leading edge and the propeller axis/plane. Measurements included propeller forces and moments, steady and unsteady wing pressures, and the far-field acoustic signature. The results show that the highest far-field overall sound pressure levels occur in the closest propeller–wing configuration. This is potentially due to the propeller being in partial ground effect with respect to the wing. It also led to an increase in the coefficients of thrust and torque on the propeller, and the coefficient of pressure on the wing upper surface. Additionally, both the tonal noise and broadband noise increased in this configuration compared the isolated propeller case. Increasing the horizontal offset between the propeller centre and the wing leading edge, and reducing the vertical distance between the two, reduced the tonal and broadband noise, while producing a similar thrust to the isolated propeller. Near-field acoustic data showed higher signal energy content at the leading edge than at the trailing edge of the wing, both for in-ground-effect (due to acoustic and hydrodynamic waves) and out-of-ground-effect (due to acoustic waves only) configurations. Varying the horizontal offset between the propeller and wing affected both the tonal and broadband amplitudes in the near-field, whereas varying the vertical separation affected only the tonal components. These findings are crucial for improving the design and noise mitigation strategies of propeller–wing systems in urban air mobility applications, where aerodynamic interactions and associated acoustic emissions directly impact performance and environmental compliance.