On the wake structure of a micro-ramp vortex generator in hypersonic flow
On the wake structure of a micro-ramp vortex generator in hypersonic flow
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高超声速流微斜坡涡发生器尾流结构研究
DOI：
10.1063/5.0030975
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发表时间：
2020-12-01
影响因子：
4.6
通讯作者：
Yuan, Xianxu
中科院分区：
文献类型：
--
作者：
Sun, Dong;Chen, Jianqiang;Yuan, Xianxu
本文采用直接数值模拟的方法研究了高超声速流动中微斜面涡发生器的尾迹结构。详细分析了尾流涡结构的整个演化过程。首先，探讨了平均速度和脉动分布的标度律。结果表明，基于超声速实验的缩比律可以直接应用于高超声速尾迹流场，在近壁面处偏差较小。在此基础上，研究了弧形涡的详细结构，发现涡腿之间并不相连。在本模拟中没有检测到完整的涡环。在尾流下游，通过分离激波时，弧形涡的强度增大。结果表明，在流场中形成了由弧形涡和剪切层组成的涡列。通过适当的正交分解，揭示了弧形涡对热流密度的影响。流向上正负相间的条带反映了弧形涡的撞击过程。相应模态的频率进一步证明了这些条纹是弧形涡的足迹。
In this paper, a direct numerical simulation is performed to study the wake structures of a micro-ramp vortex generator in the hypersonic flow. The whole evolution process of vortical structures of the wake flow has been carefully analyzed. First, the scaling laws for the profiles of mean velocities and fluctuations have been explored. The results show that the scaling laws based on the supersonic experiments can be directly applied in the hypersonic wake flow with a few discrepancies near the wall. Then, the detailed structures of arc-like vortices are examined, and the legs of vortices are found not being connected with each other. No full vortex ring is detected in the present simulation. At the downstream of the wake flow, the intensity of arc-like vortices has been augmented when passing the separation shock. The results reveal that a vortex train composed of arc-like vortices and shear layer is formed. With the help of the proper orthogonal decomposition, the impact of arc-like vortices on the heat flux has been revealed. The alternative positive and negative strips in the streamwise direction suggest the impinging process of arc-like vortices. The frequencies of the corresponding modes further prove that the strips are the footprint of arc-like vortices.