Numerical study on the jet formation of simple-geometry heavy gas inhomogeneities
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Extreme Computing Research Center
Online Publication Date2019-02-05
Print Publication Date2019-02
Permanent link to this recordhttp://hdl.handle.net/10754/631054
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AbstractThe 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.
CitationFan E, Guan B, Wen C-Y, Shen H (2019) Numerical study on the jet formation of simple-geometry heavy gas inhomogeneities. Physics of Fluids 31: 026103. Available: http://dx.doi.org/10.1063/1.5083636.
SponsorsThis work was supported by funding from the Research Grants Council of Hong Kong under Contract No. GRF 152151/16E and the Natural Science Foundation of China, No. 11772284.
JournalPhysics of Fluids