Vortex control is a thriving research area, particularly in relation to flying wing or delta wing aircraft. This paper presents the topological structures of vortex flow on a flying wing aircraft controlled by a nanosecond plasma dielectric barrier discharge actuator. Experiments, including oil flow visualization and two-dimensional particle image velocimetry (PIV), were conducted in a wind tunnel with a Reynolds number of 0.5 × 106. Both oil and PIV results show that the vortex can be controlled. Oil topological structures on the aircraft surface coincide with spatial PIV flow structures. Both indicate vortex convergence and enhancement when the plasma discharge is switched on, leading to a reduced region of separated flow.

The effects of the arrangement position and control parameters of nanosecond dielectric barrier discharge (NS-DBD) plasma actuators on lift enhancement for flying wing aircraft were investigated through wind tunnel experiments at a flow speed of 25 m s −1 . The aerodynamic forces and moments were obtained by a six-component balance at angles of attack ranging from −4°to 28°. The lift, drag and pitching moment coefficients were compared for the cases with and without plasma control. The results revealed that the maximum control effect was achieved by placing the actuator at the leading edge of the inner and middle wing, for which the maximum lift coefficient increased by 37.8% and the stall angle of attack was postponed by 8°compared with the plasma-off case. The effects of modulation frequency and discharge voltage were also investigated. The results revealed that the lift enhancement effect of the NS-DBD plasma actuators was strongly influenced by the modulation frequency. Significant control effects were obtained at f=70 Hz, corresponding to F + ≈1. The result for the pitching moment coefficient demonstrated that the plasma actuator can induce the reattachment of the separation flows when it is actuated. However, the results indicated that the discharge voltage had a negligible influence on the lift enhancement effect.

The nanosecond pulsed plasma discharge actuator is used on a flying wing aircraft. At the angles of attack rang from -4° to 28°, the impact of plasma actuator arrangement position and discharge frequency on lift-enhancement effect is tested. Oil flow visualization is used to investigate the surface flow pattern varies with angles of attack for the plasma actuator turned on and off. The result indicates that lift-enhancement can be achieved through the actuator discharges at large angles of attack on flying wing aircraft. The arrangement position and discharge frequency both have a significant impact on lift-enhancement effect. The actuator which arranged at the leading edge of the aircraft could get the best lift-enhancement effect. There exists an optimal discharge frequency, flow separation under this frequency can be effectively suppressed, which results the best lift-enhancement effect. The flow visualization test shows that the control mechanisms of the plasma actuator are to inject energy to the shear layer, thus increased the vortex strength. The vortices strengthen the mixing of the outer high-speed fluid with inner low-speed fluid, which effectively restrains the separation.