等离子体激励器控制平板边界层转捩实验研究

Experimental study of controlling flat transition using surface dielectric barrier discharge actuator

在低速射流风洞中,研究了单级介质阻挡放电等离子体激励器对光滑平板边界层转捩位置的控制作用。实验采用热线测量技术,以边界层速度脉动与平均速度型作为转捩判据。实验发现,在来流速度为15m/s,激励器连续放电参数为输出电压峰峰值11kV,频率4.7kHz时,在激励器放电作用下,平板边界层转捩位置推迟约40mm。在相同的来流条件和激励器布局下,研究了不同放电参数对边界层内速度型,速度脉动以及频谱分布的影响,发现提高放电电压、频率和占空比能进一步推迟转捩。实验结果表明:激励器产生的射流效应可以增强边界层流动的稳定性,随放电电压、频率以及占空比增强,射流能量增大,因此边界层稳定性进一步加强,转捩控制效果也更明显。

In a low speed jet wind tunnel,the transition point of a flat plate controlled by a single-stage dielectric barrier discharge（DBD）plasma actuator has been studied.Applying hot wire measurement technology,the transition location is judged by boundary layer velocity fluctuation and velocity profile.The flow speed of the experiments is 15m/s and the discharge parameters of the actuator are voltage peak to peak value is 11 kV,frequency is 4.7kHz.After the analysis of the velocity fluctuation of the same height within boundary layer,the results show that the transition point is delayed about 40 mm farther downstream when the actuator is working.With the same flow speed and actuator distribution,actuators with different discharge parameters and their effects on the velocity profile,velocity fluctuation and amplitude spectrum of hot-wire signal within the boundary layer have been studied.It is discovered that higher discharge voltage,frequency and duty ratio can further delay the transition point.According to the experiment results,the jet generated by the plasma actuator strengthens the fluid stability of the boundary layer.As the discharge voltage,frequency and duty ratio goes up,the power of the jet gets stronger,which further strengthens the boundary layer stability and delays the transition location.