The Experimental Studies Of Active Flow Control Based On Dielectric-barrier-discharge Plasma

Based on the dielectric-barrier-discharge(DBD) technology, whichwas introduced into active flow control in the1990s，Plasma actuator haslots of advantages, such as being simple in structure，having no compoundmoving parts，without affecting the shape of the control volume，quickresponse and can realize multiparameter regulation and control. Even moreimportant, it has high efficiency, without any additional fuel and movingparts, it also can be operated at atmospheric pressure. Because of its finecharacteristic， DBD-PA active flow control technology is likely todramatically improve vehicle performance and achieve cut-acrosstechnological development of the aeronautical technology. As a result, ithas becoming a focus and frontier at home and abroad. In recent years,Many scholars do lots of studies about the influence of DBD-PA onboundary layer flow control、 improving the turbulence intensity of theboundary layer、 increasing allowance for stall、raising wing section liftand suppressing the cavity noise.In this study, we carry out research on miniaturizing the DBD plasmaactuator, and a parametric analysis has been performed on a DBD plasmaactuator to investigate the relationship between theinduced-velocity/power-consumption with the signal wave, voltage,frequency and electrode gap, respectively. Using particle imagevelocimetry(PIV) and flow visualization technique, the starting vorticesinduced by the plasma actuator have been observed in the quiescent air,including the downstream primary vortex which is relative to the exposed electrode, the upstream opposite vortex and the secondary vortexassociated with the primary vortex. Development of the primary vortexand the opposite vortex was studied, and the mechanism of the inducedstarting vortices was discussed with comparing the flow visualization andPIV results with the discharge current wave, through experiments, weverify the correction of the mechanism that DBD-PA can generate inducedflow, meanwhile since the DBD-PA will release lots of heat duringoperation, it can heat the surrounding fluid and produce upwise buoyanceas a result.By using the experimental platform of DBD-PA, we investigate theactive control over cavity noise. In details, DBD-PA devices are assignedboth streamwise and spanwise, so as to verify the attenuation effect uponcavity noise. In addition, the size of the effective lighting area in the freestream direction is the kernel factor that determines the attenuation effect.With the varied direction of plasma by adjusting the relative positions ofDBD-PA electrode, we work on the attenuation effect resulted from theincoming plasma in different directions.