高超音速流场中锥体边界层转捩图象的纹影显示及处理

SCHLIEREN VISUALIZATION AND PROCESSING OF THE BOUNDARY LAYER TRANSITION IMAGE ON A CONE IN THE HYPERSONIC FLOW

本文介绍了一种大画幅纹影成像技本,应用该技术,显示了高超音速流场中锥体边界层转捩。将所得到的纹影图象在显微密度计图象处理系统中进行处理与测量,并结合纹影法原理进行了分析计算,得到了边界层诸截面相对密度变化曲线以及边界层转捩位置等实验结果,该结果与有关气动理论和实践结果进行了比较。

A large frame schlieren image technique is presented in the paper. The technique has been applied to visualization of the boundary layer transition on the surface of the cone in the hypersonic flow. The schlieren pictures which are obtained from wind tunnel test are processed and measured by using digital image processor (including a micro-densitometer) , they are also analysed and computed in combination with the schlieren theory, i therefore, the relative gas density values and transition region in the boundary layer flow can be shown. The measured results are compared with aerodynamic theory and other test results. The research work was carried out in CARDC. The test model is a cone of 7° semi-angle and the free flow condition is as followed: Mach number M = 10.29, Reynolds number per meter Re/L= 1.38× 107 (1/m), gas density p= 3.14× 10-5 (g/cm3 ),