Flow structures and heat transfer over a single dimple using hybrid URANS-LES methods
Flow structures and heat transfer over a single dimple using hybrid URANS-LES methods
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DOI：
10.1016/j.compfluid.2018.01.014
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发表时间：
2018-08
影响因子：
2.8
通讯作者：
J. Turnow;R. Kasper;N. Kornev
中科院分区：
文献类型：
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作者：
J. Turnow;R. Kasper;N. Kornev
采用大涡模拟（LES）和具有壁面建模能力的改进延迟分离涡模拟（IDDES），分析了窄通道内高雷诺数和Prandtl数（Re D= 105000和Pr= 3）下壁面单个凹痕的流动结构和湍流传热。通过对Re τ= 2048以下湍流通道流动的模拟，验证了LES和IDDES方法的有效性，确定了所需的网格尺寸及其在高雷诺数条件下的应用。在中等栅格尺寸下，高雷诺数下的换热率和摩擦系数与经验相关系数基本一致，而低雷诺数下的换热率和摩擦系数差异较大。分析了球面凹窝的平均值、高阶统计量以及涡结构和二次流结构，并与实验数据进行了比较。IDDES再现了平均量和非对称流结构，并以令人满意的精度大大减少了计算时间。
Large eddy simulations (LES) and improved delayed detached eddy simulations with wall modeling capability (IDDES) are applied to analyze flow structures and heat transfer of turbulent flow over a single dimple placed at the lower wall in a narrow channel for high Reynolds and Prandtl numbers up to Re D= 105000 and Pr= 3 respectively. Based on the simulations of the turbulent channel flow up to Re τ= 2048, the LES and IDDES methods are validated, needed mesh sizes and its application for high Reynolds numbers are determined. The heat transfer rates and the skin-friction factors of the IDDES are consistent with empirical correlations whereas LES show large differences for higher Reynolds numbers using moderate grid sizes. The mean values, high order statistics as well as vortex structures and secondary flow structures of a spherical dimple have been analyzed and compared to experimental data. IDDES reproduces mean quantities and the asymmetric flow structures with a changing orientation towards the main flow while reducing the computation time enormously with a satisfying accuracy.