Abstract:Based on the flow characteristics of the dielectric-barrier-discharge (DBD) plasma actuator, a novel circulation control technique has been proposed, which is used to control flow around a NACA0012 airfoil. Since the trailing edge of the NACA0012 airfoil is not a circular surface, the circulation control technique is constructed from two DBD plasma actuators. One is attached to the suction surface near the trailing edge, with its induced wall jet to the same direction with the free stream. The other is attached to the pressure surface near the trailing edge, with its induced wall jet to the opposite direction with the free stream. Time-resolved PIV is employed to measure the velocity field in the near-wake region, with the Reynolds number based on the airfoil chord length Re=20000. With the plasma circulation control, a steady recirculation region could be formed on the pressure surface near the trailing edge, acting as the virtual aeroshaping effect, thus the flow over the suction surface is accelerated, while the velocity over the pressure surface is reduced. Thus both the suction and pressure over the airfoil are enhanced, increasing the circulation over the airfoil. The dynamic force balance measurements further validate the efficiency of the lift improvement by the present plasma circulation control. The plasma control increases the lift coefficients over the entire angles of attack.