中文摘要：

利用高阶紧致格式,采用直接数值模拟（DNS）和线性稳定性（LST）分析方法,对高超声速边界层的失稳机制和转捩特点进行了研究.通过对马赫数为6的2°攻角高超声速钝锥边界层的稳定性分析发现：小攻角高超声速钝锥边界层存在多枝不稳定模态;周向速度使钝锥的稳定性特征与不考虑周向速度时有本质的差别;转捩线在接近背风面处出现拐折现象是由失稳模态发生转换引起的.

英文摘要：

DNS（direct numerical simulation） and LST（linear stability theory） were employed as tools to study the characteristics of instabilities and transitions in hypersonic boundary layers.The characteristics for flow past a blunt cone in Mach 6 free-stream with 5 half-angle at 2 degree angle of attack（AOA） were analyzed.The results show that there are multi branch instability modes.The instabilities of the blunt cone with the crossflow generated due to AOA is essential different from the cases without the crossflow.The crook in the transition front near the leeward line arises from a transformation between the instability modes.