平流层表面介质阻挡放电等离子体流动控制相似准则验证

Verification on Similarity of SDBD Plasma Induced Jet for Stratospheric Flow Control

基于翼型Reynolds相似和等离子体射流相似准则,可在地面等效模拟位于平流层的等离子体流动控制效果。首先通过表面介质阻挡放电（SDBD）实验确定地面和平流层激励器的几何参数和放电参数,使等离子体射流具有相同的Reynolds数;然后采用几何、放电参数已知的激励器来控制翼型在地面和平流层飞行时（Reynolds数相同）的流动分离;最后采用数值模拟得到地面和平流层等离子体放电前后的翼型升力系数。结果表明：在施加流动控制后,翼型在地面条件飞行时的升力系数增幅与平流层基本一致。模拟平流层的准确度与翼型攻角有关,在临界攻角处偏差相对较大,其余攻角处偏差很小。在施加等离子体流动控制后,翼型在地面条件飞行的升力系数与平流层的升力系数在临界攻角处的偏差率在1.27%-5.26%之间;其余攻角处较小,在0.04%-0.98%之间。

Based on the jet Reynolds-similarity theory, the plasma jet flow control performance in stratosphere can be equivalently simulated in ground conditions. Firstly, the SDBD experiment was conducted to determine the geometrical and electrical parameters, which ensured the plasma actuator to get the same Reynolds number of induced jets in ground and stratosphere,respectively. Then, the actuator, whose geometrical and electrical parameters were known, was applied to control the airfoil flow separation, and the airfoil had the same Reynolds number in ground and stratosphere with different velocities.Finally, the airfoil lift coefficients before and after plasma jet discharges in ground and stratosphere were obtained through numerical simulation. It is found that, with the plasma flow control, the airfoil lift coefficient in ground increases nearly equally to that in stratosphere. The deviation of airfoil lift coefficients of ground and stratosphere at the critical angle of attack is large while it is small at the rest. With the plasma flow control, the deviation of the lift coefficients of ground and stratosphere ranges from 1.27% to 5.26% at the critical attack angle, and it ranges from 0.04% to 0.98% at the rest.