Abstract: In order to investigate the unsteady flow characteristics of a two-dimensional supersonic/hyper.sonic inlet during accelerating start process，two dimentional unsteady numerical simulation were performed on2-D inlet with internal contraction ratio 1.63. The results show that there are two categories of oscillation in theflow field from unstart to start condition，namely，high-frequency oscillation and low-frequency oscillation. The non-oscillatory state，low-amplitude and high-frequency oscillation，high-amplitude and low-frequency oscilla.tion and started state appears one by one with the increase of free-stream Mach number. The frequency of high-frequency oscillation is about 664Hz，the low-frequency oscillation with a base frequency of 62～100Hz and sec. ond frequency below 200Hz. In addition，The duration of high-amplitude and low-frequency oscillation is muchlonger than that of low-amplitude and high-frequency oscillation. The main factor leading flowfield oscillation isthe flow which is choked at the throat. The mentioned secondary oscillation is the result of the disturbance of sepa.ration zone formed and broken down on the cowl side.

Key words: Two-dimensional inlet； Acceleration process； Unsteady； Flow oscillation； High internal contraction ratio；Numerical simulation

摘要： 为了研究二元超 /高超声速进气道在加速起动过程中流动的非定常特性，采用二维非定常数值计算方法对内收缩比为 1.63的进气道流场进行了数值模拟。研究结果表明，进气道在加速起动过程中，从不起动到起动转变时流场存在两种类型的振荡，即高频振荡与低频振荡。随着来流马赫数的增加，流动依次经历无振荡状态、低幅高频振荡状态、高幅低频振荡状态、起动状态。其中，高频振荡的频率为 664Hz，低频振荡的主频率在 62～100Hz，二次谐振频率低于 200Hz，且高幅低频振荡持续的时间远大于低幅高频振荡的。喉道壅塞是造成流场振荡的主要因素，而观测到的二次谐振现象是由唇罩侧分离区的非定常形成和消失而导致的。

关键词: 二元进气道 ;加速过程 ;非定常 ;喘振 ;大内收缩比 ;数值模拟中图分类号:V231.3文献标识码:A文章编号:1001-4055(2018) 07-1494-10 DOI:10.13675/j. cnki. tjjs. 2018. 07. 007