ABSTRACT Direct Numerical Simulations (DNS) of forced homogeneous isotropic turbulence in a dense gas (FC-70), accurately described by a complex EoS, are computed for a turbulent Mach number of 0.8. In a numerical experiment, results are compared to the ones obtained when considering the fluid as a perfect gas. It is found that the dense gas displays a deeply modified shocklets' structure. The amplitude of compression shocklets jumps in pressure, density and entropy is divided by an order of magnitude with respect to the perfect gas. Moreover, expansion shocklets are found in the dense gas flow, also associated with small jumps in pressure, density and entropy. Comparing TKE spectra, the same inertial range is found regardless of the EoS. By comparing the terms of the filtered TKE equation for the dense and perfect gas EoS, it is found that for FC-70 and the present turbulent Mach and Taylor Reynolds numbers, the SGS deformation work is the only significant term in the inertial regime and does not significantly change with the EoS. A preliminary analysis of the flux terms responsible for the total energy conservation shows that the pressure term PDF is however significantly modified by the thermodynamic properties of the fluid.

中文翻译：

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稠密气体中受迫均匀各向同性湍流的直接数值模拟

摘要 稠密气体 (FC-70) 中强制均匀各向同性湍流的直接数值模拟 (DNS)，由复杂的 EoS 准确描述，计算湍流马赫数为 0.8。在数值实验中，将结果与将流体视为理想气体时获得的结果进行比较。发现致密气体显示出深度改变的激波结构。相对于理想气体，压缩激波的压力、密度和熵跃变的幅度除以一个数量级。此外，在稠密的气流中发现了膨胀激波，这也与压力、密度和熵的小跳跃有关。比较 TKE 光谱，无论 EoS 如何，都可以找到相同的惯性范围。通过比较稠密气体和完美气体 EoS 的滤波 TKE 方程的项，发现对于 FC-70 和目前的湍流马赫数和泰勒雷诺数，SGS 变形功是惯性状态中唯一的重要项，并且不会随 EoS 发生显着变化。对负责总能量守恒的通量项的初步分析表明，流体的热力学性质显着修改了压力项 PDF。