可压缩混合层中细光束畸变效应的实验研究

利用双曝光CCD相机成像技术,对小直径光束穿越可压缩混合层流场存在的大尺度结构特性及其引起的气动光学效应进行了实验研究。实验研究结果表明:在不同对流马赫数(Mc=0.17,0.45)下,可压缩混合层中的大尺度结构形状不同,因而具有不同的折射率分布场,从而导致光束投影发生了不同程度的变形和偏移。利用光束质心的概念定量分析了不同对流马赫数下光束偏移和抖动的统计特性。统计结果表明在高对流马赫数下光束投影的偏移量减小,光束沿流场展向的平均偏移角度减小,但摆动幅度加大。

Experimental Research on Small Diameter-light-beam Aberration in a Compressible Mixing Layer

Characteristics of small diameter light beam traversing a compressible mixing layer where exists large-scale structure and its induced aero-optical effect were experimentally studied by using double-exposure CCD camera imaging system.Results show that the shape of large-scale structure is distinct from one another for different convective Mach number(Mc=0.17,0.45),its configuration is often different at different moment even for same convective Mach number due to the different distribution of refractive index.Quantitative statistical property analysis of light beam excursion and shaking was carried out for different convective Mach number based on concept of beam centroid.Statistical results show that for high convective Mach number,the excursion of light beam projection decreases,the average excursion angle of light beam along flow field also decreases,but the shaking amplitude increases.