非定常等离子体激励对大攻角流动分离控制的数值模拟研究

Numerical Simulation of Flow Separation Control by Plasma Actuator in Burst Mode at Large Angles of Attack

应用交流电(alternating current,AC)介质阻挡放电(dielectric barrier discharge,DBD)等离子体流动控制由于其结构简单、响应频率快、可实现实时定量控制等优点,正在成为等离子体流动控制技术的重点研究方向。结合基于分离涡模拟(detached eddy simulation,DES)和等离子体唯象体积力模型的方法研究非定常等离子体激励对NACA0015翼型在攻角为20°情况下流动分离控制。结果表明:非定常等离子体激励在高雷诺数、大攻角下对翼型分离具有明显的控制效果,可以达到增升减阻目的,且流动控制效果比定常激励效率更高;非定常等离子体激励流动控制与定常等离子体激励流动控制机理不同,非定常等离子体激励通过促进分离区内速度脉动,对流场产生非定常的干扰,使得分离剪切层提前失稳,增强流场涡结构的掺混,从而抑制流动分离。

Application of alternating current(AC)dielectric barrier discharge(DBD)plasma flow control is becoming the key research direction in plasma flow control technology due to its simple structure,fast response frequency,and the ability to achieve real-time quantitative control.The effect of flow separation control by plasma actuator in burst mode on NACA0015 airfoil at an angle of attack of 20°was investigated by using the method of detached eddy simulation(DES)separation vortex simulation and plasma-only body force model.The results show that the burst mode has a significant control effect on the airfoil under the condition of high Reynolds number and large angle of attack,it can achieve the purpose of increasing lift and reducing drag,and the flow separation control effect is more efficient than the steady mode.The mechanism of burst mode is different from the steady mode.The plasma actuator in burst mode suppresses the flow separation by promoting the velocity pulsation in the separation zone to produce unsteady interference in the flow field,which makes the separation shear layer destabilize earlier and enhances the mixing of the flow field vortex structure.