At present, the control capability of dielectric barrier discharge (DBD) plasma actuation covers the flow velocity range of helicopter’s retreating blades, so it is necessary to extend it to the dynamic stall control of rotor airfoils. A DBD plasma actuator was adopted to control the dynamic stall of an oscillating CRA309 airfoil in this paper. The effectiveness of alternating current (AC) DBD plasma actuation on reducing the area of lift hysteresis loop of the oscillating airfoil was verified through pressure measurements at a Reynolds number of 5.2 × 105. The influence of actuation parameters on the airfoil’s lift and moment coefficients was studied. Both steady and unsteady actuation could effectively reduce the hysteresis loop area of the lift coefficients. The flow control effect of dynamic stall was strongly dependent on the history of angle of attack. Compared with the steady actuation, unsteady actuation had more obvious advantages in dynamic stall control, with reducing the area of lift hysteresis loop by more than 30%. The effects of plasma actuation on the airfoil’s flow field at both upward and downward stages were discussed at last.

The experimental system was established to explore the plasma flow control effect for helicopter rotors in hover mode. With the plasma actuator applied at the leading edge of the rotor’s blades, AC-DBD (alternating current dielectric barrier discharge) plasma actuation was generated by a sinusoidal AC high voltage generator. By direct force measurement, the influence of actuation parameters on the rotor’s aerodynamic performance was investigated at the tip Reynolds numbers of 1.7×105. The AC-DBD actuation can delay the blade stall to more than 3° with about 20% increase in the thrust coefficient at the post-stall pitch. At a constant motor power driving the rotor, AC-DBD actuation could reduce the rotor’s torque at the stalled pitch and increase the rotational speed of the rotor. Also, AC-DBD actuation could maintain a relatively high hover efficiency of the rotor at large collective pitches. In a wide range of actuation parameters, the AC-DBD plasma actuation could improve the rotor’s aerodynamic performance at large blade pitches. High-speed photography of the tuft motion on the blade’s upper surface showed that the AC-DBD plasma actuation could promote the reattachment of the blade’s separation flow.

At present, the control capability of dielectric barrier discharge (DBD) plasma actuation covers the flow velocity range of helicopter’s retreating blades, so it is necessary to extend it to the dynamic stall control of rotor airfoils. A DBD plasma actuator was adopted to control the dynamic stall of an oscillating CRA309 airfoil in this paper. The effectiveness of alternating current (AC) DBD plasma actuation on reducing the area of lift hysteresis loop of the oscillating airfoil was verified through pressure measurements at a Reynolds number of 5.2×105. The influence of actuation parameters on the airfoil’s lift and moment coefficients was studied. Both steady and unsteady actuation could effectively reduce the hysteresis loop area of the lift coefficients. The flow control effect of dynamic stall was strongly dependent on the history of angle of attack. Compared with the steady actuation, unsteady actuation had more obvious advantages in dynamic stall control, with reducing the area of lift hysteresis loop by more than 30%. The effects of plasma actuation on the airfoil’s flow field at both upward and downward stages were discussed at last.