High-Fidelity Modeling of Multirotor Aerodynamic Interactions for Aircraft Design

Electric aircraft technology has enabled the use of multiple rotors in novel concepts for urban air mobility. However, multirotor configurations introduce strong aerodynamic and aeroacoustic interactions that are not captured through conventional aircraft design tools. This paper explores the capability of the viscous vortex particle method (VPM) to model multirotor aerodynamic interactions at a computational cost suitable for conceptual design. A VPM-based rotor model is introduced along with recommendations for numerical stability and computational efficiency. Validation of the individual rotor is presented in both hovering and forward-flight configurations at low, moderate, and high Reynolds numbers. Hovering multirotor predictions are compared with experimental measurements, evidencing the suitability of the proposed model to capture the thrust drop and unsteady loading produced by rotor-on-rotor interactions.