Study on the Flow Control of the Airfoil Dynamic Stall Using the Co-flow Jet

Dynamic stall control is of great significance for enhancement of the airfoil aerodynamic characteristics. In the present study, the co-flow jet(CFJ) flow control method is numerically investigated to control the dynamic stall caused by the pitching airfoil. Two aspects regarding the CFJ implementation are studied: one is the effect of the CFJ channel on the dynamic stall characteristics when the jet is switched off and another is the effect of jet momentum coefficient on the dynamic stall control effectiveness when the CFJ is activated. Results show that the jet channel will significantly affect the aerodynamic characteristics in the attached flow regime during pitching up, but not have obvious influence on the aerodynamic characteristics in the massively separating regime during the pitching down process. When the jet is activated, the dynamic stall characteristics is significantly improved. The areas of the hysteresis lines are significantly reduced, and the lift is significantly increased, and drag is reduced. The peaks of the drag and moment are significantly reduced. Moreover, the negative damping existing in the moment coefficient hysteresis line of the baseline airfoil is removed, leading to a completely positive damping during the entire pitching cycle.