Large eddy simulation of channel flow with and without periodic constrictions using the explicit algebraic subgrid-scale model
Large eddy simulation of channel flow with and without periodic constrictions using the explicit algebraic subgrid-scale model
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DOI：
10.1080/14685248.2014.929292
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发表时间：
2014-07
影响因子：
1.9
通讯作者：
A. Rasam;S. Wallin;G. Brethouwer;A. Johansson
中科院分区：
文献类型：
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作者：
A. Rasam;S. Wallin;G. Brethouwer;A. Johansson
我们分析了显式代数亚网格尺度 (SGS) 应力模型 (EASSM) 在平面河道流大涡模拟 (LES) 中的性能以及具有流向周期性山形收缩（周期性山形收缩）（周期性山流）引起分离的河道中的流动。 LES 是使用 Code_Saturne 执行的，Code_Saturne 是一种非结构化并置有限体积求解器，具有二阶空间离散，适用于复杂几何形状中不可压缩流的 LES。首先，使用 Code_Saturne 和伪谱方法分析了 EASSM 在两种不同分辨率下平面河道流 LES 中的性能。据观察，EASSM 对平均速度和雷诺应力的预测比传统的动态 Smagorinsky 模型 (DSM) 更准确。一般来说，伪谱方法的结果更准确。第二步，将具有周期性山流中流动分离的 EASSM 的 LES 与具有 DSM、无 SGS 模型和使用 DSM 的高分辨率 LES 数据的 LES 进行比较。结果表明，与 DSM 和无 SGS 模型模拟相比，EASSM 对平均速度分布、摩擦和压力系数、再循环气泡的长度和形状以及雷诺应力的预测要好得多。还观察到，在域的某些部分，解析的应变率和 SGS 剪切应力具有相同的符号。与 EASSM 相比，DSM 在这种情况下无法产生正确的 SGS 应力。
We analyse the performance of the explicit algebraic subgrid-scale (SGS) stress model (EASSM) in large eddy simulation (LES) of plane channel flow and the flow in a channel with streamwise periodic hill-shaped constrictions (periodic hill flow) which induce separation. The LESs are performed with the Code_Saturne which is an unstructured collocated finite volume solver with a second-order spatial discretisation suitable for LES of incompressible flow in complex geometries. At first, performance of the EASSM in LES of plane channel flow at two different resolutions using the Code_Saturne and a pseudo-spectral method is analysed. It is observed that the EASSM predictions of the mean velocity and Reynolds stresses are more accurate than the conventional dynamic Smagorinsky model (DSM). The results with the pseudo-spectral method were, in general, more accurate. In the second step, LES with the EASSM of flow separation in the periodic hill flow is compared to LES with the DSM, no SGS model and a highly resolved LES data using the DSM. Results show that the mean velocity profiles, the friction and pressure coefficients, the length and shape of the recirculation bubble, as well as the Reynolds stresses are considerably better predicted by the EASSM than the DSM and the no SGS model simulations. It was also observed that in some parts of the domain, the resolved strain-rate and SGS shear stress have the same sign. The DSM cannot produce a correct SGS stress in this case, in contrast to the EASSM.