Comparison of Numerical Modeling Approaches for Flow over a Wing with an Upstream Rotor

View Video Presentation: https://doi.org/10.2514/6.2022-1332.vid

Efforts towards maximixing the aerodynamic performance of eVTOL aircraft have led to the integration of multiple propellers in close proximity of lifting surfaces. This work models an infinite rotor-wing unit at two angles of attack (AOA) of 8 and 12 degrees based on the CRC-20 quad-rotor biplane developed by the US army using different turbulence modeling approaches including unsteady Reynolds-averaged Navier-Stokes (URANS), delayed detached eddy simulation (DDES) and large eddy simulation (LES) approaches. The actuator line model (ALM) is employed to represent the rotor as it captures key flow features including unsteadiness in the rotor wake while offering attractive computational cost saving and ease of implementation. Vortical structures from the rotor-wing unit are presented first. Results highlight LES's ability in resolving the complex on-wing vortical structures and their interaction with the rotor wake. Spanwise variation of boundary layer transition is observed in the upstroke and downstroke portions of the wing. In addition, averaged results are presented for power, thrust and sectional wing forces from different modeling approaches at 12 degrees AOA. Significant differences are seen in sectional forces.