Flow control on a high-lift wing with microsecond pulsed surface dielectric barrier discharge actuator

Abstract

In this study, microsecond pulsed surface dielectric barrier discharge (mSDBD) is utilized to improve the aerodynamic characteristics of a high-lift wing. First, the characteristics of the mSDBD were tested qualitatively by a Schlieren system, revealing that the thermal perturbation induced by rapid heating is the main flow feature of the mSDBD at low working frequency. Subsequently, wind tunnel experiments were conducted at a free-stream speed of 45 m/s (Re=1.34×106) to investigate the effects of discharge frequency on the aerodynamic performance of the wing. Results indicate that there is an optimal excitation frequency or frequency band, at which the flow instability can be effectively excited. In this optimal situation, the relative improvement of the maximum lift coefficient reaches 9.1% and the stall angle is delayed by 4°. Besides, the flow control mechanisms with mSDBD actuation were analyzed by Large-eddy simulation (LES). The large-scale vortex induced by fast gas heating creates two negative pressure zones near the wing root and tip, both of which are crucial for lift augmentation. Moreover, when plasma actuation is applied to the case of small flap deflection, comparable or even better flow control effects are obtained, in reference to the case of large flap deflection but without plasma actuation. Based on these experimental and simulation results, a novel concept of plasma-actuator-enhanced high-lift wing was proposed.