Abstract
A virtual blade method (VBM) combining the unsteady momentum source model with the computational fluid dynamics solver is applied in this work. The momentum source term is employed to replace the effect of the rotor blade on the air in the unsteady Reynolds-averaged Navier–Stokes equations, and the unsteady characteristics of the rotor flow field are accurately captured without body-fitted grids. The rotor aeroacoustic computation model is then combined with the Ffowcs Williams and Hawkings (FW–H) equation. Taking the Caradonna–Tung rotor, GIT rotor fuselage model, and AH-1/OLS rotor model as examples, the aeroacoustic computation effectiveness for blade tip vortex capturing in hover and rotor/fuselage aerodynamic interactions is validated by available experimental data. The results show that the VBM can accurately simulate the rotor wake, unsteady load, and aerodynamic noise at a low computational cost. Compared with the body-fitted grid method, the flow field computation time of the VBM is reduced by 3/4, and the amount of data for VBM/FW–H acoustic postprocessing is reduced by more than 90%.
