Shock wave structure in rarefied polyatomic gases with large relaxation time for the dynamic pressure
Shock wave structure in rarefied polyatomic gases with large relaxation time for the dynamic pressure
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DOI：
10.1088/1742-6596/1035/1/012009
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
S. Taniguchi;T. Arima;T. Ruggeri;M. Sugiyama
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文献类型：
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作者：
S. Taniguchi;T. Arima;T. Ruggeri;M. Sugiyama
基于扩展热力学理论分析了稀薄多原子气体中的激波结构。特别是，大松弛时间的动态压力，这对应于大体积粘度的情况下，被认为是通过采用最简单的版本的扩展热力学只有6个独立的领域（ET6），质量密度，速度，温度和动态压力。最近，通过基于动力学理论的数值分析[S Kosuge and K Aoki：Phys. Rev. Fluids，Vol. 3，023401（2018）]证实了ET的理论预测的有效性。结果表明，在小马赫数或中等大马赫数情况下，采用多原子椭球统计模型的数值结果与ET的理论预测一致。在本文中，首先，我们在相同的假设条件下，即气体是多变的，体积粘度与温度成正比的情况下，比较了ET6的理论预测与动力学理论在大马赫数下的预测。其次，分析了非多变气体中大马赫数时的激波结构，特别关注比热和体粘滞系数的温度依赖性对激波结构的影响。通过对稀薄CO2气体的分析，表明这些温度依赖性在精确分析强激波结构中起着重要作用。
The shock wave structure in rarefied polyatomic gases is analyzed based on extended thermodynamics (ET). In particular, the case with large relaxation time for the dynamic pressure, which corresponds to large bulk viscosity, is considered by adopting the simplest version of extended thermodynamics with only 6 independent fields (ET6); the mass density, the velocity, the temperature and the dynamic pressure. Recently, the validity of the theoretical predictions by ET was confirmed by the numerical analysis based on the kinetic theory in [S Kosuge and K Aoki: Phys. Rev. Fluids, Vol. 3, 023401 (2018)]. It was shown that numerical results using the polyatomic version of ellipsoidal statistical model agree with the theoretical predictions by ET for small or moderately large Mach numbers. In the present paper, first, we compare the theoretical predictions by ET6 with the ones by kinetic theory for large Mach number under the same assumptions, that is, the gas is polytropic and the bulk viscosity is proportional to the temperature. Second, the shock wave structure for large Mach number in a non-polytropic gas is analyzed with the particular interest in the effect of the temperature dependence of specific heat and the bulk viscosity on the shock wave structure. Through the analysis of the case of a rarefied carbon dioxide (CO2) gas, it is shown that these temperature dependences play important roles in the precise analysis of the structure for strong shock waves.