分界面厚度方法在气动光学波前失真仿真中的研究

Interfacial-thickness-method in simulation of aero-optical wavefront distortions

将气动光学波前失真与流体力学特性联系起来,通过分界面厚度研究湍流流场物理结构和气动光学波前失真的关系.利用导弹绕流流场的计算流体力学数据,采用高折射率梯度分界面代替完整折射率场模拟流场的光学效应.将其结果和光直接传播通过原始流场所计算出的光程差比较,发现仅利用50%的折射率高梯度模拟的流场计算出的光程差与原始流场计算出的光程差具有很好的一致性.实验结果表明:高梯度分界面能较好模拟大尺度气动光学效应.折射率分界面方法对于气动光学失真的预测与校正具有一定的指导意义,也可用于控制高速流场,抑制气动光学失真的研究.

The optical-wavefront distortions are related with the fluid-mechanical behavior in this paper. Interracial-Thickness-Method (ITM) is deduced fi'om eikonal equation.The turbulent re&active-index field is simulated using high-refractive-index gradient interfaces instead of the full turbulent information.In this simulation method,the turbulent flow optical behaviors are characterized by refractive index field,the interfacial physical thickness are introduced as the inverse of the refractive index gradient magnitude,and the optical wavefront distortions are quantified by the optical path difference (OPD),Modeled optical path difference (OPD) profile is compared with the full OPD profile,and it found that they agree well.The results show that large-scale aero-optical distortions emerge from high-gradient interfaces and the ITM approach is useful to simulate aero-optical effects.