Impact of Off-body Schemes on Hovering Rotor WakBreakdown and Predicted Performance

Wake breakdown is a common phenomenon in eddy-resolving computational fluid dynamics simulations of helicopter rotors in hover. Such breakdown can affect the prediction of rotor torque, which is greatly dependent on the fidelity of the simulation and its ability to resolve rotor tip vortices. In some cases, young-age tip vortices can interact with broken-down features in the wake, which may cause errant predictions of rotor torque. In this work, variations in the choice of off-body numerical scheme are explored in order to determine the impact of these parameters on the state of the rotor wake and the predicted performance. The NASA OVERFLOW 2.3d solver is employed with hybrid RANS/LES modeling enabled. The wake state of the rotor is compared qualitatively and quantitatively across the parameter sweep. Additional analyses focus on the effect of the quadratic constitutive relation on the preservation of vorticity in the wake.