AC-DBD等离子体激励对低速平板湍流边界层的减阻试验研究

Experimental Study of AC-DBD Plasma Actuator on the Drag Reduction of Low-speed Turbulent Boundary Layer

为了研究等离子体激励对湍流边界层的减阻机理,采用交流介质阻挡放电(AC-DBD)的等离子体激励阵列。试验使用热线风速仪和高频粒子图像测速仪(PIV)获取边界层速度分布,平板模型放置在南京航空航天大学0.8m低速直流风洞试验段中(来流速度为11m/s),激励器布置形式为顺来流放置,主要研究不同激励电压下对湍流边界层的减阻效果。研究结果表明,在施加不同电压等离子体激励后得到了不同程度的减阻效果,减阻效果随电压增大出现先增大后减小的趋势,减阻率最大达5.29%。等离子体激励减小了边界层对数区的速度分布,抑制相干结构的发展,削弱相干结构的强度,从而达到减阻的效果。

AC Dielectric Barrier Discharge(AC-DBD)actuation can reduce the resistance of turbulent boundary layers.This paper investigates the drag reduction mechanism of AC-DBD using the hot-wire method and particle image velocimetry.The array plasma actuator was arranged downstream of the incoming flow with a velocity of 11m/s.The plate model was placed in the 0.8m low-speed DC wind tunnel of Nanjing University of Aeronautics and Astronautics.The results show that the drag reduction effects of plasma excitation under different voltages are different.The drag reduction effect shows a trend of increasing and then decreasing with the voltage increase.The maximum drag reduction rate is 5.29%,which inhibits the development of the coherent structure and weakens the strength of the coherent structure,thereby achieving the effect of drag reduction.The velocity results for the boundary layer show that plasma excitation suppresses the development of coherent structures by reducing the velocity profile in the logarithmic region of the boundary layer.This effect weakens the strength of the coherent structure,thereby achieving the effect of drag reduction.