Validation of an actuator surface model with CFD convected wake model for hover and forward flight

Navier-Stokes CFD simulations using body-fitted grids and overset or sliding mesh methods are capable of predicting rotorcraft aerodynamics. However, such simulations are often time-consuming to configure and computationally expensive to run. A new CFD-coupled actuator surface model has been developed to alleviate these problems. The model combines an unsteady lifting-line representation of the rotor blades with a wake model composed of vortex filaments and the coupling with the finite volume, incompressible Navier-Stokes solver is two-way. Performance predictions for the S-76 rotor in hover are accurate over a range of operating conditions and satisfactory predictions are also produced for the unsteady blade loading on the UH-60A rotor in high-speed forward flight.