纳秒脉冲等离子体分离流控制频率优化及涡运动过程分析

将纳秒脉冲驱动的介质阻挡放电等离子体激励器应用到NASA SC（2）-0712翼型上，在迎角分别为15°和20°时，开展了在不同雷诺数下的分离流动控制研究。通过模型表面静压测量，得到了不同激励频率下的分离流动控制效果。对翼型表面压力进行分布积分，得到了在不同雷诺数和激励频率下的升力系数，表明分离流的控制效果有一个较宽的激励频率范围，只要激励频率落在相应的频带范围内，均能实现有效的分离抑制。流动显示结果表明，分离流的控制在瞬时表现为放电后可形成大尺度旋涡拟序结构。旋涡的周期性产生、运动和演化造成了分离剪切流动的动态变化过程，从而促进了高/低速气流的动态掺混。

Frequency optimization and vortex dynamic process analysis of separated flow control by nanosecond pulsed plasma discharge

The nanosecond pulsed plasma discharge actuator is used on a NASA SC (2)-0712 airfoil. At the angles of attack of 15° and 20°, the flow control efficacy of the actuators is tested at a series of Reynolds number conditions. The static pressure test result shows that the actuator has different control effect at different forcing frequencies. By calculating the lift coefficient, the relations between the forcing frequency and lift are determined, which shows that the broadband bandwidth of flow reattachment makes the flow control more practicable. The flow visualization test shows that the pulse discharge promotes the formation of large scale vortexes. The coherent structures of the vortex couples are periodically produced, move and evolution. This process brings the separated shear layer dynamic evolution, and thus promotes a dynamic mixing of high/low speed airflow to happen in the separated flow region.