Aerodynamics and Aeroacoustics Studies of Helicopter Hover; a Computational Approach Using LES

Blade-vortex interaction (BVI) is one of the major phenomena affecting the helicopter aerodynamics and aeroacoustics, and implicitly the helicopter’s aerodynamics performance and stability. Understanding and prediction the BVI phenomenon still pose significant challenges both experimentally and computationally. Experimental studies of BVI are difficult due to the fact that data acquisition in the rotating frame is challenging. Moreover, the BVI experiments are costly due to the wind tunnel configuration. On the other hand, computational studies of BVI are more feasible, at a much lower cost. Therefore, the present research is carried out using the computational approach, namely the large-eddy simulation approach. The present study is carried out for high Reynolds number Re=106, based on the blade tip speed velocity and chord of the blade. A three-blade rotor disk configuration is used in the present study. The study shows that the BVI effect is most significant in the 25% span of the blade measured from the tip of the blade. The time-varying pressure exhibits an increase of its peaks towards the tip of the blade, and it increases with the increase of the rotational speed of the blade.