低速翼型分离流动的等离子体主动控制研究

为了研究等离子体激励器的放电形式及其诱导气流的规律，以及翼型迎角、自由来流速度分别对翼型流动分离抑制效果的影响。在低速、低雷诺数条件下利用介质阻挡放电等离子体激励器对NACA0015翼型进行了主动流动控制研究。结果表明：介质阻挡放电的形式为丝状放电；等离子体激励器诱导气流的方向由裸露电极指向覆盖电极，由电极的布置方式决定，与接线方式无关；当来流速度为25m／s，雷诺数为2．03×10^5时，等离子体气动激励可以有效地抑制翼型吸力面的流动分离，翼型最大升力系数增大约为9．7％，翼型l临界失速迎角由17．5°增大到20．5°；翼型失速延迟的真正原因并非单纯的气流加速；等离子体激励器的作用效果随着来流速度的提高而减弱，研究非定常激励或等离子体激励器与流场之间的耦合效应，也许更加具有潜力。

Study on the Plasma Active Control in the Low-speed Airfoil Separation Flow

The discharge pattern, the characteristics of flow induced by plasma aerodynamic actuation, and the impacts of angle of airfoil and free flow speed on the airfoil flow separation suppression effect are investigated respectively. Active flow control investigation of NACA 0015 airfoil by stagger electrode dielectric barrier plasma actuation is performed under low velocity and Reynolds number conditions. The results indicate that the mode of dielectric barrier plasma discharge is filamentary discharge; the direction of the flow induced by the plasma actuator is from the upper electrode down to the bottom electrode, which depends on the distribution of electrodes and has nothing to do with the actuator’s wiring mode; when the inflow velocity is 25 m/s, corresponding Reynolds number is 2.03×105, plasma aerodynamic actuation can effectively suppress flow separation on the suction side of the airfoil, which causes a 9.7% augment of maximal coefficient of lift, and the stall angle of the airfoil increases from 17.5° to 20.5°. The real reason for the stall delay of airfoil is not a simple gas acceleration; it has been discovered that the effectiveness of the plasma actuation decreases as the speed of free flow increases, further exploration of unsteady plasma excitation or the coupling effect between plasma and flow field, maybe have great potential.