On the effect of operating condition on separated-flow control by nanosecond pulse discharge actuators

Abstract

The surface dielectric barrier discharge plasma actuator driven by nanosecond pulses is recognized as an effective fluid actuator for flow separation control. The operation condition of nanosecond dielectric barrier discharge actuators for separated flow control still requires further study, particularly prioritizing the improvement of the effectiveness and reducing energy consumption in flow separation control implementation. In this study, experiments are conducted using a two-dimensional NASA SC(2)-0712 airfoil in a wind tunnel with a Reynolds number of 0.5 Â 10 6 (25 m/s). The pressure measurement experiments show that the location of actuators affects the efficiency of separation control. Particle image velocimetry results indicate that the most efficient location of the actuator is upstream of the separation point and near the original point of the separated shear layer. Meanwhile, the particle image velocimetry results show the vorticity attaches to the airfoil wall after discharge, which suggests that the reattachment is due to the generation of large-scale vortices. These present structures result in the mixing of the shear layer with the main flow thereby delaying separation and reattaching a separated flow. This study shows the most efficient location related to the separation point. Furthermore, it indicates the reattachment of flow is attributed to the motion of vortexes coherent structure.

Vortex dynamics over an airfoil controlled by a nanosecond pulse discharge plasma actuator at low wind speed

“…Furthermore, a lab-made Z-style schlieren device is used to visualize the temporal and spatial characteristics of the pressure wave generated by the discharge of the NS-DBD actuator (details of the test method can be found in reference [28]). The schlieren experiments are conducted in still air, and the peak-to-peak discharge voltage is also 15.3 kV.…”