Rotor Wake Computations for Direct Integration with Current CFD Technology

The technical objective is to develop methodology and tools suitable for the integration of more efficient but accurate rotor wake computations within current unstructured CFD computations. The proposed method avoids the use of computationally intensive full overset rotor computations with attached refined grids to capture and track the blade tip vortex. Instead, we propose a 3 components methodology. First is an enhancement of existing actuator disk models to include an accurate representation of the tip vortex and helical motion in the wake. This is achieved by employing tip vortex strength as additional constraint in modeling the loading distribution on the actuator disk, and by treating the rotor disk as a rotational reference frame. Second and the main ingredient of the methodology is a novel vorticity preserving technique that is fully dynamic, avoiding any tuning parameters, to counter the inherent numerical dissipation. This will allow accurate modeling of the rotor wake dynamic and in turn its interaction with the solid surface of the main body. The third component is the use of a flexible multi codes coupling framework to enable simulations of different rotor models and configurations in a plug and play fashion without specific modifications of the main flow solver.