Closed-loop control of dynamic stall on a pitching airfoil with tandem configuration of plasma actuators

This study numerically investigates closed-loop control strategies for mitigating dynamic stall on a pitching National Advisory Committee for Aeronautics (NACA) 0012 airfoil using tandem dielectric barrier discharge plasma actuators. The unsteady Reynolds-Averaged Navier–Stokes equations, coupled with a transitional model and an empirical plasma body force model, are employed to simulate the complex flow physics. A closed-loop control algorithm, which activates actuators based on real-time detection of the incipient flow separation point, is developed and compared against open-loop actuation and a baseline (no-control) case. Key performance metrics, including lift-to-drag ratio enhancement, aerodynamic damping augmentation, and reattachment characteristics, are evaluated across various actuator excitation frequencies. Results demonstrate that the proposed closed-loop system effectively delays stall onset, advances flow reattachment to occur at higher angles of attack during downstroke, and significantly improves cycle-averaged aerodynamic damping up to 55.1% compared to baseline case. While both open-loop and closed-loop control improve the lift-to-drag ratio by approximately 13.4%–17.2%, closed-loop control achieves this with substantially reduced actuator power consumption by strategically activating only the most effective actuator. This work underscores the potential of intelligent, feedback-driven plasma actuation for enhancing the performance and stability of airfoils operating under aggressive unsteady conditions.