Multi-Fidelity Numerical Approach to Aeroacoustics of Tandem Propellers in eVTOL Airplane Mode

Abstract

The present paper deals with an innovative multi-fidelity framework for characterizing the aerodynamics and the aeroacoustics of multirotor systems with application to advanced eVTOL aircraft. In this framework, the goal of the activity is a multi-fidelity investigation of two propellers in tandem with rotor disks overlap, reproducing a typical feature of eVTOL architectures in airplane mode flight conditions. A Ffowcs Williams-Hawkings equation solver is used to compute the aeroacoustic footprint of the test case in different configurations. The solver is run with both mid-fidelity aerodynamic simulation data obtained with DUST and high-fidelity simulation data obtained with SU2. The comparison between the two different approaches highlights the suitability of the DUST mid-fidelity simulations for the aeroacoustic investigation of a propeller in airplane mode configuration with a much lower computational cost with respect to high-fidelity CFD simulations. On the other hand, the co-axial propellers tandem configuration shows some differences in the sound pressure level computed with the two approaches, mainly due to the contribution to noise emission given by the rear propeller.