Control of leading edge separation on airfoil using DBD plasma actuator with signal amplitude modulation

In this study, the separation control of an airfoil when a dielectric barrier discharge (DBD) plasma actuator is mounted on its leading edge was examined. Experiments were performed at a Reynolds number of approximately 67,000 with an external airflow of 10 m/s. The DBD plasma actuator was installed on an NACA 0015 airfoil with a 100 mm chord and 150 mm width at x/c = 0.025, where x was the vertical distance measured from the leading edge and c was the chord length. Lift force measurements, flow visualization and velocity measurements were conducted to investigate the performance of the DBD plasma actuator, which was driven by either pulse modulation with amplitude modulation (PM + AM) or pulse modulation only (PM). The PM + AM case was designed to consume the same amount of power as the PM case. The result showed that the PM + AM case improved the lift coefficient compared to the PM case for both St = 0.6 and St = 4.0. Under the stall control condition (angle of attack, α = 16°) and high angle of attack condition (α = 18°), the PM + AM case always demonstrated improved lift over the PM case; the improvement in lift was greater at α = 18° than at α = 16°. Flow visualization confirmed larger and stronger vortex shedding for the PM + AM case over the PM case.