Various strategies for hybrid RANS/LES modeling of hypersonic turbulent boundary layers subjected to strong wall-cooling are developed and analyzed. By defining a turbulent thermal length scale, the eddy viscosity and diffusivity of the hybrid model are calculated by the same formula, . This allows a similar blending of the length scales and the development of analogous dynamic models for turbulent stress and heat flux. The dynamic procedure is applied to heat transfer by equating norms, rather than invoking least-squares with a lower bound, which improves robustness. The shielding function, as used in detached eddy simulations models, is revised to prevent a spurious early switch from the RANS to the LES mode. This revision significantly improves the accuracy of hybrid models on coarse grids. Finally, the proposed models are tested and validated for Mach numbers between 2.5 and 14, and wall-to-recovery temperature ratios between 0.18 and 1.

中文翻译：

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冷壁高超声速湍流边界层的混合 RANS/LES 建模

开发并分析了强壁面冷却下高超声速湍流边界层混合 RANS/LES 建模的各种策略。通过定义湍流热长度尺度，混合模型的涡流粘度和扩散率可以通过相同的公式计算。这允许长度尺度的类似混合以及湍流应力和热通量的类似动态模型的开发。通过使范数相等，而不是调用具有下限的最小二乘法，将动态过程应用于传热，从而提高了鲁棒性。分离涡模拟模型中使用的屏蔽功能经过修改，以防止从 RANS 模式到 LES 模式的虚假早期切换。此修订显着提高了粗网格上混合模型的准确性。最后，对所提出的模型进行了测试和验证，马赫数在 2.5 到 14 之间，壁与恢复温度比在 0.18 到 1 之间。