Dual- mode scramjet engine may suffer unstart because of a large enough upstream or downstream pressure disturbance. Unstart will dramatically reduce the thrust, could compromise the stability and safety of the vehicles,so it's necessary and important to investigate the effective control methods. In this paper,fifth- order characteristic- wise WENO scheme and third- order TVD Runge- Kutta method were applied to solve the three- dimensional Navier- Stokes equations,to explore a passive control method using trips as vortex generator,and corresponding control effect on the hypersonic flow separation caused by shock wave/boundary layer interaction induced by a fin. The results showed that complicated and refined separation and attachment structures has been caught by using high order accuracy scheme, the changing law of friction and pressure at separation and attachment lines were summarized; the local stre-amwise vortex induced by trips affected the flow separation structures evidently. The pressure distribution was changed and the intensity of separation and attachment was depressed. The second separation and re-attachment lines were almost disappeared.%双模态超燃冲压发动机由于压力扰动可能发生不起动现象,造成推力严重下降,对飞行稳定性与飞行安全具有很强的破坏性.不起动初始阶段主要受到激波与边界层相互作用引起的流动分离影响,采用5阶特征型WE-NO格式与3阶TVD型Runge- Kutta格式的高精度数值方法,求解三维Navier- Stokes方程,研究了利用凸起物作为涡发生器的被动控制方法,及其对高超声速流动分离现象的控制效果.结果表明高精度数值格式能够捕捉到复杂精细的流动分离结构,总结了摩阻、压力等在分离再附位置的变化规律；发现凸起物通过诱导形成局部流向涡进行流动控制,能够改变压力分布,减弱分离强度,影响分离结构.
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