Aerodynamic and aeroacoustic experimental investigation of a three propellers DEP configuration

The study presented is part of the H2020 CS2 European project VENUS, which investigates methodologies and tools to enable a concurrent design approach for both the aerodynamics and aeroacoustics of aircraft employing Distributed Electric Propulsion (DEP). Specifically, a 3D wing model, featuring a flap and powered by three electric motor-driven propellers, underwent a comprehensive testing campaign in the large-scale, low-speed, acoustically-treated Wind Tunnel (WT) of Pininfarina, Turin (Italy). A wide range of parameters was systematically varied and studied, including the blade pitch angle, the angle of attack, flap configurations for take-off and landing, phase shifts between propellers, and different relative distances both between the propellers themselves and with respect to the wing body. The experimental tests comprise both measurements of acoustics, such as beamforming and directivity analysis, and aerodynamics, through forces and wall pressure characteristics for the different DEP geometries. The main objective of this research is to identify potential optimal DEP configurations based on the WT test results which provided the aerodynamic and aeroacoustic performances exploited by each DEP solution. More specifically, it was found that the geometric arrangement with the propellers positioned closest to the wing and with non-overlapping rotor discs offers the best compromise between aerodynamic and aeroacoustic characteristics.