Experimental investigation on the flow induced by a continuous mode sliding dielectric barrier discharge actuator in the non-starting phase

Sliding dielectric barrier discharge (SL-DBD) has demonstrated significant potential for flow control to enhance the aerodynamic performance of aircraft. The paper investigates the velocity characteristics of SL-DBD-induced flow structures during the non-starting phase in continuous mode using particle image velocimetry. The results reveal that the induced flow exhibits periodic velocity fluctuations during the non-starting phase, and the dominance of rotation and strain rates determines the flow structure characteristics. When the rotation rate dominates, the flow structure exhibits vortex behavior. Moreover, the dominance of the rotation rate is not determined by the starting vortex but is an inherent feature of the induced flow itself. When the strain rate dominates, the flow tends to stabilize. However, the rotation rate still plays a role, and the dominance of the rotation and strain rates alternates periodically. By simplifying the flow during the non-starting phase to a dynamic equilibrium state, we derived an expression for the velocity field variation, revealing that the electric field's divergence determines the velocity field's divergence. When the peak-to-peak voltage is 18 kV, the high-frequency fluctuation frequency of ux is 50 Hz, more significant than the high-frequency fluctuation frequency of uy, which is 20 Hz. The investigation demonstrates that the electric field intensity is the primary factor driving the periodic alternation between rotation rate and strain rate, and the fluctuation characteristics of the induced flow velocity are inherent properties. These findings have important implications for understanding the physical mechanisms of SL-DBD-based flow control.