In order to reveal the lift-enhancement mechanism of the dielectric barrier discharge plasma circulation control and improve the control effect on the lift

the effects of the actuation position on the airfoil aerodynamic characteristics were studied. Based on a wind tunnel experimental system

the millisecond-pulsed plasma actuation was applied on the upper and lower surfaces near the training edge of the elliptical airfoil NCCR1510-7067 N. The experimental free stream velocity was from 6 m/s to 35 m/s and the angle of attack is from-4 degrees to 12 degrees. The pressure distribution of the airfoil surface was measured by the pressure scanning valve

the lift characteristics was obtained by integral

and the flow field characteristics was shown by the smoke flow visualization experiment. The experimental results show that: 1) The lift-enhancement effect is better with the actuator arranged near the separation vortex on the upper and lower surfaces. When the actuator is arranged at 98.3% chord on the lower surface

the circulation control efficiency-cost ratio can reach 108.7 at the angle of attack of 2 degrees. 2) The action mechanisms of the upper and lower surface actuations are different. The upper plasma jet drives the external flow to form Coanda effect and delays the separation. The lower plasma jet is reverse to inflow. So it reduces the velocity and increases the pressure of the lower surface. Moreover

it induces a vortex in the same direction as the co-rotating lower separation vortex. The two vortices couple with each other and deflect the streamline down

playing a role of a virtual flap. 3) The double actuators on the upper and lower surfaces enhance each other and form a stronger Coanda effect. The effective flow velocity increases to 35 m/s and the controlling effect of plasma actuation on airfoil circulation and lift becomes stronger. The experimental results provide a theoretical basis for selecting the key parameters

increasing the efficiency and the further engineering application of plasma circulation control.