Mid-fidelity numerical investigation of the interactional aerodynamic mechanisms in an electrical vertical take-off and landing quad-rotor aircraft

The present study aims to provide a comprehensive aerodynamic characterization of a novel quad-rotor electrical vertical take-off and landing aircraft concept vehicle designed by the National Aeronautics and Space Administration. In particular, a mid-fidelity numerical approach was employed to analyze interactional aerodynamic mechanisms characterizing the flow field between the rotors and, particularly, to quantify their effects on rotor performance. With this aim, a breakdown approach was employed, starting from the simulation of a single rotor up to the complete aircraft configuration, including fuselage and rotor arm fairings. Both hover and cruise flight conditions were analyzed through numerical simulations. Numerical results highlighted small effects on vehicle aerodynamic performance in hover due to the limited interaction between rotors, while cruise conditions were characterized by more relevant interactional mechanisms leading to performance losses, particularly on the rear rotors of the aircraft.