Abstract: In view of the problem of deterioration of aerodynamic performance of the airfoil due to dynamic stall, the miniaturized actuation power supply and dielectric barrier discharge plasma actuator are employed to conduct experimental study on the plasma flow control of airfoil dynamic stall by means of dynamic pressure measurement and external trigger Particle Image Velocimetry (PIV). It is shown that the aerodynamic actuation of dielectric barrier discharge plasma can effectively control the airfoil dynamic stall, improve the average aerodynamic force, increase aerodynamic efficiency, and reduce the hysteresis loop region when aerodynamic force varies with the angle of attack. The plasma actuator induces vortex near the leading edge, which promotes the separation flow reattaching to the airfoil surface. The plasma increases the suction of 0.2-0.4 chord length region of the upper surface, and weakens the second, third and fourth order energy of the Power Spectral Density (PSD) distribution. The average lift coefficient is increased by 7.1%, the stall angle of attack is delayed by 1.3°, and the hysteresis loop region is decreased by 4.5%; at the angle of attack of 4°-9°, the plasma actuator reduces the average drag coefficient of the airfoil by 40%. With the increase of the oscillation frequency, the unsteady performance of the flow around airfoil is enhanced, and it is more difficult to suppress the dynamic separation vortices at higher Reynolds number. In these cases, it is necessary to increase the plasma actuation intensity to achieve better control effect.

Key words: airfoil, dynamic stall, flow control, plasma, dielectric barrier discharge, wind tunnel test