Experimental Investigation Of Transition Location Measurement And Control Based On A Variety Of Measurement Methods

In this paper, the surface oil film interferometry and hot wire/film devices have been used to measure the transition location of different models under a flow speed of Ma=0.6 and lower speeds.The experimental technical details of each measurement methods have been discussed. Based on the results, surface rough elements array and surface dielectric barrier discharge have been used to control the model transition locatioin under different flow speeds. The mechanism of different control methods has been analyzed.According to this paper, after some necessary improvements, surface oil film interferometry can be applied to measure surface friction and transition location under high flow speed. The results showed a same law comparing to computational results.Besides, surface roughness elements array can be successfully applied to model bypass transition control under subsonic flow. The height and space between rough elements both affect the control effect, but the height of the element has a more significant impact. Surface dielectric barrier discharge can be successfully applied to delay model transition location under low flow speed. The control principle is that the jet generated by the plasma actuator strengthened the fluid stability of the boundary layer. Better transition control effect can be achieved by stronger jet induced by higher actuator voltage and frequency. Above these, opinions have been raised on applying plasma actuators to higher speed transition based on the experimental results.