Dynamic evolution of vortex structures induced bytri-electrode plasma actuator

Plasma flow control is a new type of active flow control approach based on plasma pneumatic actuation.Dielectric barrier discharge(DBD) actuators have become a focus of international aerodynamic research.However,the practical applications of typical DBDs are largely restricted due to their limited discharge area and low relative-induced velocity.The further improvement of performance will be beneficial for engineering applications.In this paper,high-speed schlieren and high-speed particle image velocimetry(PIV) are employed to study the flow field induced by three kinds of plasma actuations in a static atmosphere,and the differences in induced flow field structure among typical DBD,extended DBD(EX-DBD),and tri-electrode sliding discharge(TED) are compared.The analyzing of the dynamic evolution of the maximum horizontal velocity over time,the velocity profile at a fixed horizontal position,and the momentum and body force in a control volume reveals that the induced velocity peak value and profile velocity height of EX-DBD are higher than those of the other two types of actuation,suggesting that EX-DBD actuation has the strongest temporal aerodynamic effect among the three types of actuations.The TED actuation not only can enlarge the plasma extension but also has the longest duration in the entire pulsed period and the greatest influence on the height and width of the airflow near the wall surface.Thus,the TED actuation has the ability to continuously influencing a larger three-dimensional space above the surface of the nlasma actuator.

Flow control performance evaluation of a tri-electrode sliding discharge plasma actuator

Tri-electrode sliding discharge(TED)plasma actuators are formed by adding a direct current(DC)exposed electrode to conventional dielectric barrier discharge(DBD)plasma actuators.There are three TED modes depending on the polarity and amplitude of the DC supply:DBD discharge,extended discharge and sliding discharge.This paper evaluates the electrical,aerodynamic and mechanical characteristics of a TED plasma actuator based on energy analysis,particle image velocimetry experiments and calculations using the Navier-Stokes equation.The flow control performances of different discharge modes are quantitatively analyzed based on characteristic parameters.The results show that flow control performance in both extended discharge and sliding discharge is more significant than that of DBD,mainly because of the significantly higher(up to 141%)body force of TED compared with DBD.However,conductivity loss is the primary power loss caused by the DC polarity for TED discharge.Therefore,power consumption can be reduced by optimizing the dielectric material and thickness,thus improving the flow control performance of plasma actuators.