Gurney-Flap Drag Penalty Reduction with a DBD Plasma Actuator

The present research proposed a method to reduce the Gurney-flap drag penalty with a dielectric barrier discharge (DBD) plasma actuator, which was mounted in front of the Gurney flap to generate a countercurrent wall jet. The research was based on numerical simulation, which was performed on a NACA 0012 airfoil with Gurney-flap heights (h) of 1, 2, and 3%c at Rc=6.84×105. According to the simulation results, the wall jet was able to decrease the additional drag on the Gurney flap by lowering the upstream pressure of the Gurney flap without disturbing the flow field downstream of the Gurney flap. The drag reduction effect was more obvious at low angles of attack and small Gurney-flap height, and a drag reduction of 15% was achieved at α=0° with 1%c flap height. This method also lowered total lift, but it was not strong enough to impair the high-lift property of the Gurney flap. For all tested Gurney-flap heights, the lift-drag ratios under low to moderate CL were enhanced by this approach. Comparing with the clean airfoil, a 12% increment of lift-drag ratio was obtained at cruise with plasma control at h/c=1% flap height.