非定常激励下等离子体DBD诱导涡特性研究

Characteristics of vortex induced by DBD plasma actuator under unsteady excitation in quiescent air

在非定常激励下,等离子体DBD诱导涡是影响等离子体流动控制效果的关键因素,研究静止大气下DBD诱导涡结构特性对进一步理解等离子体DBD流动控制机理具有重要意义。采用高频PIV与高速纹影系统对静止大气下DBD诱导涡结构进行了研究,通过λ2法则分析了诱导涡涡核移动规律,获得了非定常激励下诱导涡的演化规律以及脉冲频率对诱导涡结构以及尺度的影响。在一定脉冲频率内,DBD诱导涡生成速率与脉冲频率一一对应,诱导涡涡核移动方向与壁面呈16°～21°,随着脉冲频率的增加,诱导涡尺度逐渐变小,且越来越靠近壁面。全文总结了不同脉冲频率下涡的相互作用以及黏性耗散对诱导涡发展过程的影响。

The vortex induced by DBD plasma actuator under unsteady excitation is an important factor in plasma flow control. It is of great significance to study the characteristics of vortex induced by DBD plasma actuator under static atmosphere for further understanding of plasma DBD flow control mechanism. In this paper, the structures of vortex induced by DBD plasma actuator under static atmosphere are studied by high-frequency PIV and high-speed schlieren system. The trajectory of induced vortex movement was analyzed by the λ 2 definition, and the influence of burst frequency on induced vortices under unsteady excitation is obtained. The number of vortices induced by DBD is strictly in correspondence with the burst frequency. The induced vortex’s cores move along the wall surface from 16° to 21°. As the burst frequency increases, the scales of induced vortices gradually become smaller and closer to the wall. Also, the interaction between the induced vortices at different burst frequencies during the movement of induced vortices was analyzed.