Numerical study on the jet formation of simple-geometry heavy gas inhomogeneities
Numerical study on the jet formation of simple-geometry heavy gas inhomogeneities
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简单几何重气体不均匀射流形成的数值研究
DOI：
10.1063/1.5083636
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发表时间：
2019-02
影响因子：
4.6
通讯作者：
Hua Shen
中科院分区：
文献类型：
--
作者：
E.Fan;Ben Guan;Chih-Yung Wen;Hua Shen
平面激波作用下气体不均匀射流的形成是一个与激波会聚密切相关的有趣现象。在这项研究中，一系列的重气体不均匀性与非常简单的几何形状（正方形，矩形，圆形和三角形）的数值再现来追踪射流形成的来源。特别注意的是，导致形成特定的射流形式的波型。通过求解无粘可压缩欧拉方程，模拟了激波加速的多组分流动。采用迎风特征时空守恒元和求解元格式，采用五方程模型处理气体界面。根据数值结果解释了实验图像中出现的射流类型，并揭示了确保射流形成的典型激波模式。结果表明，射流的形成是由内部马赫干的冲击作用引起的，而射流的增长则是由内部马赫干诱导的高速气流所滋养的。射流的宽度由内部马赫杆的高度决定。几何上，在气体不均匀性中出现了被滑移线包围的焦楔，气体在焦楔中被加速。发现焦楔的存在和焦楔尖的坐标可以作为描述射流形成机理的定性判据。这些判据为理解射流形成的方向、规模和过程提供了更直观的依据。
The jet formation of gas inhomogeneities under the impact of a planar shock wave is an interesting phenomenon that is closely related to shock convergence. In this study, a series of heavy gas inhomogeneities with very simple geometries (square, rectangle, circle, and triangle) are numerically reproduced to trace the source of the jet formation. Special attention is given to the wave patterns that lead to the formation of specific jet forms. The shock-accelerated multicomponent flow is simulated by solving inviscid compressible Euler equations. An up-wind characteristic space-time conservation element and solution element scheme is adopted, and a five-equation model is used to treat the gas interface. The jet types that emerge in the experimental images are explained based on the numerical results, and a typical shock pattern that ensures the jet formation is uncovered. It is found that, physically, the jet is initiated by the impact of the internal Mach stem, and the jet growth is nourished by the high speed gas flow induced by this Mach stem. The width of the jet is determined by the height of the internal Mach stem. Geometrically, a focal wedge enveloped by slip lines emerges in the gas inhomogeneity, in which the gas is accelerated. It is found that the existence of the focal wedge and the coordinates of the wedge tip can be used as qualitative criteria to illustrate the mechanism of the jet formation. These criteria provide a more intuitive basis for understanding the direction, scale, and process of jet formation.
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影响因子：
4.6
作者：
S. Balasubramanian;G. Orlicz;K. Prestridge;B. Balakumar
通讯作者：
S. Balasubramanian;G. Orlicz;K. Prestridge;B. Balakumar
影响因子：
3.7
作者：
Zhai Zhigang;Wang Minghu;Si Ting;Luo Xisheng
通讯作者：
Luo Xisheng
影响因子：
3
作者：
RICHTMYER, RD
通讯作者：
RICHTMYER, RD
DOI：
10.1016/j.jcp.2009.12.030
发表时间：
2010-05
期刊：
J. Comput. Phys.
影响因子：
--
作者：
Xiangxiong Zhang;Chi-Wang Shu
通讯作者：
Xiangxiong Zhang;Chi-Wang Shu
影响因子：
2.2
作者：
Lindl, John;Landen, Otto;Baxamusa, S. H.
通讯作者：
Baxamusa, S. H.