Instability of wave complex resulting from oblique detonation decoupling

斜爆轰解耦引起的波复合体不稳定性

Oblique detonation wave(ODW)has been investigated widely for application in ramjet-type engines,but there are less works concerning its instability in a confined space.Recently,a wave complex induced by ODW decoupling has been observed,and this study investigates the instability of this wave complex featuring a recirculation zone.Numerical results show that the wave complex with recirculation zone oscillates,but the oscillations are found to be periodic rather than random,never reported before.The dependence of the period and frequency on the corner location and angle are analyzed in detail,with very irregular motion tracks of recirculation zone cores.Further quantitative analysis by Fast Fourier transformation reveals two origins of instability:one is the basic oscillation of the recirculation zone associated with the movement of surrounding wave complex;the other is self-excitation inside the recirculation zone,which makes its motion tracks more complicated than the external wave configuration.

斜爆轰波(ODW)在冲压发动机中的应用已得到广泛的研究,但对于其在受限空间中的不稳定性研究较少.最近,观察到由ODW解耦引起的波复合体,本研究考察了具有回流区的波复合体的不稳定性.结果表明,具有回流区的波复合体是振荡的,但振荡是周期性的,而不是随机的,这是以前从未报道过的.本文详细分析了周期和频率与拐角位置和角度的关系,以及回流区核心的不规则运动轨迹.通过快速傅里叶变换进一步定量分析,揭示了两个不稳定性的来源:一个是与周围波复合体运动相关的回流区的基本振荡;另一个是由回流区内部的自激发导致,这使其运动轨迹比外部波结构更复杂。