混合层二维大尺度结构光学传输效应理论分析

Theoretical analysis of aero-optical effect in the two-dimensional large-scale structure of compressible mixing layer

本文主要讨论了可压缩混合层二维大尺度结构引起的光学畸变特性.在混合层发展的第二阶段,由于混合层流场中二维拟序结构的存在改变了法向压力在空间的分布特性,在量级分析的基础上给出了法向压力梯度的动力学表达式;并由此分析了细光束在二维大尺度结构内部发生偏折的动力学原因.研究结果表明:在混合层界面处湍动能的空间分布特性与混合层内部雷诺切应力(ρu'v')累计效应的流向梯度之间的相互比较会导致细光束发生偏折.

The optical aberration by two-dimensional large-scale structure in a compressible mixing layer has been investigated. The theoretical analysis shows that normal dynamical pressure cannot keep a constant due to the existence of two-dimensional large-scale structure, and presents its expression correlative with fluid dynamic behaviors. Based on the dynamical pressure derivation, deflection angle of a small beam light through the mixing layer is obtained. The results also show that the distribution of turbulent kinetic energy and streamwise derivative of Reynolds stress （ -pu＇v＇ ） determines the deflection angle.