Synergistic effects of cavity shape and DBD plasma actuator on aerodynamic characteristics of NACA4412 airfoil

This study investigates the aerodynamic efficacy enhancement of a NACA4412 airfoil using three-dimensional large eddy simulation analysis by integrating hybrid flow control techniques. The research focuses on the combined effects of cavity-based passive flow control and a dielectric barrier discharge plasma actuator aiming to increase lift and reduce drag particularly at higher Angles of Attack (AOA). Simulations were conducted at a Reynolds number of 3.1 × 10⁶ over an AOA range of 0°–20°. Four distinct cavity shapes, circular, rectangular, triangular, and curved rectangular, were analyzed, and the cavities were placed near the trailing edge on the pressure side while the plasma actuator was positioned at 2% of the chord length near the leading edge. The interaction between cavities and plasma actuation is found to mitigate flow separation by inducing vortex generation, which promotes smaller-scale vortex structures and narrows the wake. At lower AOA, cavities alone enhance lift by 20% to 30% while at higher AOA, the combination of cavities and plasma actuation achieves lift improvements of 94% to 106%. The combined system of the circular cavity and plasma actuator reduces drag at higher AOA by up to 27.56% which significantly enhances aerodynamic efficiency, and this combination yields the greatest lift to drag ratio. Vortex structure visualizations around the cavities reveal delayed flow separation and improved flow stability. Rectangular cavities alone show notable lift increases at lower AOA, and their combination with plasma actuation further reduces drag by up to 11% at higher AOA. This study demonstrates the efficacy of integrating passive and active flow control strategies for superior aerodynamic performance, highlighting their potential for high-performance airfoil applications at elevated angles of attack.