Experimental Investigayion Of The Cylinder Wake Modified By Plasma Actuator

Flow around circular cylinder has been extensively studied from 19th centuryThe present experimental study focus on the effect of plasma actuator on thecylinder wake modified by changing input voltage,excitation frequency,duty cycle,electrode configuration systematically.The Reynolds number range used in the study is range to 0.525×10~4 to 1.58×10~4.Based on the experimental results,it is found that with the plasma actuation,themaximum drag reduction are 57.6%and 21%at Re=0.525×10~4 with linear plasma actuation in the case of V_a=11 kV,and Re=1.05×10~4 with linear plasma actuation in the case of V_a=11 kV,respectively.At Re=0.525×10~4,the maximum drag reduction achieved by the actuation of the sawtooth plasma actuator is 47.4%in the case of h/w=0.35,V_a=11 kV,F~+=2.0 and DC=70%.As the Reynolds number increases from0.525×10~4 to 1.05×10~4,the drag reduction due to plasma actuator is significantly weakened.In the case of unsteady actuation,the maximum drag reduction almost achieved at DC=50%with more energy saved.It can be noted from the fluid visual experiment that the boundary layerseparation position has been moved to the rear of the cylinder surface with plasma actuation in the case of h/w=0.10,V_a=11 kV,F~+=1.5 and DC=50%.By comparing with the plain cylinder wake,it can be seen that the wake structure has changed significantly,and it is clear that the Kármán vortex shedding has been suppressed.