钝体头部边界层特征谱分析和转捩途径预测  

Analysis of the eigenvalue spectrum and forecast of the transitional ways of a boundary layer over a blunt cone

作　　者：袁湘江[1,2] 张涵信[1,2] 沈清[3] 涂国华[1,2] 

机构地区：[1]中国空气动力研究与发展中心,四川绵阳621000 [2]国家计算流体力学实验室,北京100083 [3]航天空气动力技术研究院,北京100074

出　　处：《实验流体力学》2008年第B12期78-82,98,共6页Journal of Experiments in Fluid Mechanics

基　　金：国家自然科学基金资助（10321002,10672012）.

摘　　要：利用线性稳定性理论，分别对钝头体高超声速绕流边界层中的亚声速区域、跨声速区域和超声速区域的特征谱进行了系统分析。结果表明，根据线性稳定性理论，所分析的各速度范围流场，对所有单频波的扰动都是稳定的。但随速度的增加，稳定波的衰减率越来越低；随激波到物面距离的增加，S族扰动波相速度的实部向无量纲速度1靠拢，说明头部主激波的作用在一定意义上与平面槽道流动的上壁面相似；研究工作还表明，流场中存在着低衰减率扰动波，且无论那个速度范围内的流场，其最低衰减率扰动波的相速度实部都在0．7左右。根据钝头体特征谱分析，本文可能发生的“bypass”型转捩机理进行了理论分析，提出了几条可能的“bypass”型转捩途径。Using linear stability theory, the eigenvalue spectrum of a hypersonic boundary layer over a blunt cone, respectively, in the subsonic region, transonic region and supersonic region, were studied. The results showed that all these flow fields analyzed above is stabile. The decay rate of disturbance waves is smaller at the place where the velocity at the outer edge of the boundary layer is higher. With increasing the distance from the shock wave surface to the body, the real part of the phase velocity of the S family waves moves towards dimensionless speed 1. these calculations suggest that the effect of the nose shock, in a sense, resembles the upper boundary of channel flows. It is suggested that the disturbance waves with smaller decay rate modes exist in the flow field, but the real part of the phase velocity of the disturbance wave with the smallest decay rate is 0.7 about, in any speed flow zone. Based on these results above, the mechanisms by which these modes could lead to transition were discussed. A few ways which ways could cause transition were presented.

关 键 词：紧致格式 非线性 转捩 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]