Multi-fidelity Aerodynamic and Acoustic Design and Analysis of aHeavy-lift eVTOL

This work presents the processes used to support the preliminary design of a large eVTOL vehicle at the University of Glasgow in collaboration with GKN Aerospace. To support the GKN heavy-lift eVTOL design, known as Skybus, a range of tools of various fidelity levels were adopted and integrated. The paper first proposes and demonstrates a multi-fidelity approach for the vehicle propeller design. The propeller pitch-RPM maps were also proposed and were demonstrated to be an efficient tool for the intuitive performance visualisation, fast and accurate performance prediction, and graphic interpolation of operating conditions. High-fidelity CFD simulations of the complete Skybus vehicle in forward flight with two and four operating propellers were later carried out. The propeller operating conditions were determined through the performance maps. Near-field acoustics of the vehicle was extracted directly from the flow solutions. Detailed discussions of the flow details and the acoustic sources due to aerodynamic interference were presented. Far-field noise features were also computed using the FW-H equations and the CFD solutions. The noise levels of the heavy-lift vehicle were about 70-75 dB perceived on the ground. Considerable differences in the noise directivities of two- and four-rotor configurations were observed and discussed.