Control of leading edge separation on airfoil using DBD plasma actuator

Abstract

This study deals with the separation control of an airfoil when a dielectric barrier discharge (DBD) plasma actuator is mounted on its leading edge. The experiments were performed at Reynolds number, Re ≈ 67,000 in an external airflow of 10 m/s. The DBD plasma actuator was installed at x/c = 0.025 of a NACA0015 airfoil with a 100-mm chord and 150-mm width. Flow visualization, lift force and velocity measurements were conducted with on and off modes of the actuator (pulse-modulated drive). We found that the application of pulse modulation condition was able to delay a stall up to angle of attack α =17° compared to the Duty = 100% (α =15°). At α =17°, the maximum lift coefficient C_l was obtained for a non-dimensional pulse modulation frequency St of 4.0. With an increase in α, the lift coefficient C_l decreases sharply after reaching a maximum, which is entirely different from the case of St = 0.6, where the value of C_l falls gradually. For a high angle of attack (α =18°) that exceeds the maximum C_l, St = 0.6 produces a better lift improvement than when St = 4.0. Our results showed that the separation when St = 4.0 is larger than that when St = 0.6. In addition, we also found that there is an optimum actuation time of about 0.25 ms.