超声速尾迹-剪切流的混合增强

超声速条件下燃料和空气之间的高效混合是超然冲压发动机技术上的主要挑战。基于大涡模拟和流动稳定性分析，针对超声速尾迹-剪切流动开展了混合增强方法研究。尾迹的存在改变了混合层流动的速度剖面，对流动稳定性产生了重要影响，使混合层由三维最不稳定变为二维最不稳定，最不稳定扰动波频率和增长率增大。基于流动稳定性结果引入扰动的混合增强方式依然有效，根据稳定性结果设计了波纹隔板。数值结果表明：二维波纹壁引入的扰动未能增长，不具备混合强化效果，而三维波纹壁引入的扰动能够快速增长，具有混合强化效果，且波纹壁参数越接近最不稳定扰动波参数，混合强化效果越明显。

Mixing enhancement of supersonic wake shear layer

The efficient mixing of fuel and air at supersonic speed is the main challenge of scramjet technology. Based on analysis of large eddy simulation and hydrodynamic stability, the methods of mixing enhancement are studied in the supersonic wake shear flow. The existence of a wake component alters the profile of mean velocity, and has an important influence on the hydrodynamic stability. The existence of a wake component makes the most unstable modes of mixing layer from the three-dimensional to the two-dimensional, and the frequency and growth rate of the most unstable wave increase. The method of mixing enhancement of introducing disturbances in the mixing layer is still effective based on the analysis of hydrodynamic stability. According to the stability analysis, the parameters of wavy wall are designed. The numerical simulations observe that the disturbance introduced by the two-dimensional wavy wall cannot grow and almost has no mixing enhancement effect, while the disturbance introduced by the three-dimensional wavy wall can grow rapidly and has mixing enhancement effect. The closer the parameter of the wavy wall is to the parameter of the most unstable disturbance, the more obvious the mixing enhancement effect is.