Abstract A hybrid dynamic subgrid-scale model (HDSM) pertaining to Large-eddy simulation (LES) has been developed. The coefficient obtained by German dynamic Smagorinsky model (DSM) was integrated with a new dynamic coefficient, based on the dynamic subgrid characteristic length and controlled by the subgrid-scale (SGS) motions. In HDSM, the characteristic wave number determining the characteristic length of the dynamic subgrid is calculated from a new energy weighted mean method when the subgrid scale turbulent kinetic energy and the dissipation wave number are known. The dissipation wave-number is derived from the SGS turbulent kinetic energy spectrum equation. The total dissipation rate spectrum equation is based on the Pao energy spectrum and local equilibrium assumption. The dynamic subgrid characteristic length could take into account the rapidly fluctuating small scale behaviours and the spatial variation of turbulent characteristics. HDSM was used to simulate the fully developed channel and turbulent flow past a circular cylinder, and to determine the impact of the dam-break flow on downstream structure. The HDSM is robust in respect to anisotropic mesh and is less sensitive to grid resolution, and would accurately describe the energy transfer from large-scale to SGS fluctuations and capture more fluctuations of turbulence with same meshes compared to the DSM.

中文翻译：

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用于大涡模拟的混合动态 Smagorinsky 模型

摘要 已经开发了一种与大涡模拟 (LES) 有关的混合动态子网格尺度模型 (HDSM)。德国动态Smagorinsky模型（DSM）获得的系数与新的动态系数相结合，基于动态亚网格特征长度并受亚网格尺度（SGS）运动控制。在HDSM中，当子网格尺度湍动能和耗散波数已知时，决定动态子网格特征长度的特征波数采用新的能量加权平均法计算。耗散波数是从 SGS 湍流动能谱方程导出的。总耗散率谱方程基于 Pao 能谱和局部平衡假设。动态子网格特征长度可以考虑快速波动的小尺度行为和湍流特征的空间变化。HDSM用于模拟完全发展的通道和通过圆柱体的湍流，并确定溃坝流对下游结构的影响。HDSM 在各向异性网格方面具有鲁棒性，并且对网格分辨率不太敏感，并且与 DSM 相比，可以准确地描述从大尺度到 SGS 波动的能量转移，并捕获更多具有相同网格的湍流波动。并确定溃坝水流对下游结构的影响。HDSM 在各向异性网格方面具有鲁棒性，并且对网格分辨率不太敏感，并且与 DSM 相比，可以准确地描述从大尺度到 SGS 波动的能量转移，并捕获更多具有相同网格的湍流波动。并确定溃坝水流对下游结构的影响。HDSM 在各向异性网格方面具有鲁棒性，并且对网格分辨率不太敏感，并且与 DSM 相比，可以准确地描述从大尺度到 SGS 波动的能量转移，并捕获更多具有相同网格的湍流波动。