Circular jet with annular backflow using a dielectric barrier discharge plasma actuator (Effect of backflow on circular jet diffusion)

In the present study, the influence of the direction of the backward plasma-induced flow generated by a plasma actuator (PA) on the jet flow was investigated. In the case of the backflow PA, the centerline velocity was increased by the contraction of the main flow near the nozzle exit due to the influence of the backflow. The fluctuation of the jet boundary layer became stronger as the duty ratio was increased. Based on these factors, it is considered that the backflow by the plasma-induced flow effectively works on the diffusion of the jet structure. Furthermore, experiments were conducted by varying the Reynolds number as Re = 1.0×103 (the effect of the induced flow is large) and Re = 3.0×103 (the effect of the induced flow is small), and the difference in jet diffusion due to the induced flow effect was confirmed.