Hybrid flow control of airfoil dynamic stall using dielectric-barrier-discharge plasma actuator and Gurney flap

Abstract

To suppress dynamic stall-induced aerodynamic degradation of pitching National Advisory Committee for Aeronautics 0012 airfoils, this paper presents a hybrid active and passive flow control method using a leading-edge burst-mode dielectric-barrier-discharge (DBD) plasma actuator and a trailing-edge Gurney flap (GF, height = 0.02c). Two-dimensional unsteady Reynolds-averaged Navier–Stokes simulations are performed at Re = 7.5×104 and reduced frequency k = 0.1 to compare vortex evolution, surface pressure/friction distributions, and aerodynamic hysteresis across baseline, standalone GF, standalone DBD, and hybrid control cases. Results show that a standalone GF not only increases the peak lift coefficient by 20.2% (from 1.997 to 2.401) by strengthening dynamic stall vortex (DSV) compared to the baseline but also leads to higher peak drag and a more negative pitching moment. In contrast, standalone DBD plasma actuation injects high-momentum wall jet near the leading edge to eliminate leading-edge laminar separation bubbles, fragments large-scale DSV, and reduces the lift hysteresis loop, drag, and alleviates the negative pitching moment. However, this approach inevitably leads to a lower peak lift coefficient of 1.881. The hybrid method synergistically integrates the lift-enhancing effect of the GF with the stall-delaying capability of the DBD actuator, achieving a peak lift coefficient of 2.186, which is 16.2% higher than the DBD-only case. Meanwhile, the hybrid control reduces the peak drag coefficient by 22.5% relative to the GF-only case and alleviates the nose-down pitching-moment peak, demonstrating a distinct synergistic effect.