圆锥脉冲等离子体诱导流场特性分析

对等离子体诱导流场特性进行研究,有利于解决双稳态非对称分离涡带来的连续比例控制困难的问题。在封闭光学玻璃箱体内,应用介质阻挡放电等离子体对20°顶角圆锥附近静止大气进行了定常和脉冲循环控制,对等离子体诱导的圆锥截面绕流速度场进行了二维PIV测量,对定常控制和脉冲循环控制下最大绕流速度及最大轴向涡量进行了比较分析。实验结果表明：相对于定常控制模式,脉冲循环控制下沿垂直于圆锥截面对称面径线分布的时间平均切向速度和轴向涡量范围较广;在脉冲循环控制下,动量传递的主要表现在离散涡的形成而不是气流的加速。

Characteristics of Flow Field Induced by Periodic-pulsed Plasma over a Conical Cone

Research of flow characteristics induced by periodic-pulsed plasma can solve the problem of control continuous difficulties brought by two steady state asymmetric separation vortexes.A pair of plasma actuators is added behind the original plasma actuator pair over a 20° conical forebody to extend the angle of attack range for lateral control.Flow induced by the additional actuator in a still air chamber with one atmospheric pressure is investigated using a two-dimensional particle image velocimetry.The effects of pulse duty ratio and pulse frequency on the induced maximum crossflow velocity and maximum axial vorticity are compared with those of steady discharge.The tests indicate that the ensemble-averaged tangential velocity profile along a radial line perpendicular to the body symmetry plane induced by periodic-pulsed discharge is thicker than that of steady actuation.This is caused by formation of stronger discrete vortices that leave the cone surface in the unsteady actuation case.The main mechanism of momentum transfer under periodic-pulsed actuation is the formation of discrete vortices,rather than the gas acceleration.