光学头罩绕流流场气动光学效应数值模拟

以红外成像制导技术在高速拦截器上的应用需求为背景,进行了光学头罩绕流流场气动光学效应数值模拟.应用雷诺平均NS方程并选取了适当的湍流模型,对凹窗、凸窗和球头3种光学头罩的高速飞行器绕流流场进行了数值模拟,得到了绕流流场密度分布;研究了脉动流场引起的气动光学传输效应的计算方法,应用几何光学、物理光学和统计光学方法进行了光学传输效应计算,得到了点扩散函数,即像面光强分布.通过瞄视误差、Strehl比、含能半径等气动光学效应参数描述了流场引起的成像畸变,并分析了不同外形、飞行状态和光学系统参数对光学传输效应的影响.

Numerical simulation of aero-optical effects for the flow field around the optical window

Based on the demand of applying infrared imaging guidance system to the high speed interceptor,the aero-optical effects in the flow fields around the optical window of the high speed interceptor were simulated numerically.The density distribution of flow fields around three typical optical windows,including cavity window,raised window and sphere window,were calculated by adopting the Reynolds averaged Navier-Stokes equations with the proper turbulence model.The method to calculate the aero-optical transmission effects caused by the fluctuating flow field was discussed.The optical transmission effects were calculated using the ray tracing method,Fourier optics and statistics optics.The point spread function,which was the distribution of light intensity on the image plane,was obtained.The parameters of the optical transmission effects were presented to describe the image aberrations,such as theboresight error,Strehl ratio,and the contain energy radius.The influence of the window shape,flight state and the parameters of the optical system on the optical transmission effect were also discussed.