Time-accurate simulation of flow past PZL W-3A "Sokół" (Falcon) helicopter main rotor in forward flight

The paper presents the results of numerical simulations based on the URANS approach and the chimera overlapping grids technique of the main PZL W-3A "Sokół" (Falcon) helicopter rotor in forward flight conditions. The low-speed flight case models the helicopter rotor as parallel to the ground keeping forward speed of approximately 99km/h. Strong Blade-Vortex Interaction (BVI) is responsible for a high level of vibration and noise. The high-speed (266km/h) case reveals two main problems of modern helicopters: compressibility effects due to strong shock-wave boundary layer interaction on the advancing side and separation leading to a dynamic stall on the retreating side of the rotor. An attempt is made to correlate the results of the simulations with the very limited flight test data.