Abstract: Unstart is an abnormal operating state for hypersonic inlets，which will bring fatal effects to the flight control and vehicle. A new control method for the hypersonic inlet unstart caused by downstream mass-flow choking based on a movable slot-plate is brought forward and investigated by wind tunnel experiments. High-speed Schlieren imaging and time-resolved pressure measurements are used simultaneously to record the unsteady flow structures and surface pressures of the controlled process. Experiment results indicated that with the help of the spillage which affords the discrepancy of the capture ability and the exhaust capability of airflow during this oscillation cycle，the control method is effective to control the oscillation caused by the unstart，whatever the movable slots placed on the cowl downstream the throat or on the ramp upstream the throat. While the slots are opened，the amplitude of the pressure oscillation will decrease gradually. The frequency of the oscillation will be retained with the slots on the cowl side，while the frequency will increase with the slots on the ramp side for the extending subsonic region in the duct. Besides，the slots placed on the ramp side can improve the restart ability of the inlet by removing the separation bubble，which comes out during the unstart process.

Key words: Hypersonic inlet；Unstart control；Movable slot-plate；Restart；Experimental study

摘要： 针对高超声速进气道的不起动振荡现象，提出了一种基于滑动多缝板的进气道不起动振荡控制概念，并对相关控制方案以及流动机理开展了风洞实验研究。实验中采用高速纹影技术和动态压力测量技术对整个控制过程中的瞬态流动结构和壁面动态压力信号特征进行了记录。结果表明:无论是在喉道后的唇罩上还是喉道前的压缩面上设置多缝板，均可在进气道不起动时通过泄流平衡进气道进出口流量差，进而达到抑制振荡的目的；随着多缝板的开启，进气道内的压力振荡幅度均不断减小，但是振荡频率的变化却并不相同，相较唇罩开缝方案中的频率保持不变，压缩面开缝方案中的振荡频率将随着通道内亚声速区的不断增大而升高；此外，压缩面开缝方案相较唇罩开缝方案能够对不起动过程中产生的分离包卸除，因而能够增强进气道的再起动能力。

关键词: 高超声速进气道；不起动控制；滑动多缝板；再起动；实验研究