Augmentation of a leading-edge vortex circulation on pitching airfoils by a trailing-edge plasma actuator

Engineering applications such as bioinspired micro air vehicles (MAVs) generate lift through flapping wings, during which a leading-edge vortex (LEV) forms on the wing surface. This LEV, formed by dynamic increases in angle of attack, generates additional lift. Therefore, promoting LEV growth and delaying LEV detachment are key strategies for improving aerodynamic efficiency in flapping-wing flight. In this study, we attempt to augment the growth and delay the detachment of a LEV on a pitching NACA 0015 airfoil using a plasma actuator. The airfoil undergoes pitching motion with a 30-degree amplitude and reduced frequencies of 0.1–0.3 at Reynolds numbers of 10,000 and 20,000. Under these conditions, it is hypothesized that the interaction between the LEV and the trailing edge significantly affects LEV’s growth and detachment. Based on this assumption, we place the actuator at the trailing-edge. The lift coefficient is successfully increased by 16.5% on average over time. Surface pressure and flow field measurements reveal three aerodynamic effects induced by plasma actuation at the trailing edge: (1) suppression of trailing-edge flow separation, (2) delay of LEV detachment, and (3) enhancement of LEV circulation. These findings show a novel approach to control LEV dynamics and offer promising applications to enhance the aerodynamic performance of engineering applications.