Bi-stable flow around tandem cylinders of different diameters at low Reynolds number
Bi-stable flow around tandem cylinders of different diameters at low Reynolds number
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DOI：
10.1088/0169-5983/43/5/055506
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发表时间：
2011-10
影响因子：
1.5
通讯作者：
Yangyang Gao;S. Étienne;Dingyong Yu;Xikun Wang;S. Tan
中科院分区：
文献类型：
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作者：
Yangyang Gao;S. Étienne;Dingyong Yu;Xikun Wang;S. Tan
本文对不同直径的串列圆柱绕流进行了数值研究。上游与下游圆柱体直径比保持恒定在d/D=2/3的值，并且中心到中心的距离从1.2D变化到5D。本研究中使用的基于上游圆柱体直径和自由流速度的雷诺数等于200。力系数和流动频率已经从2D流体流动有限元模拟中获得。单尾流脱落，再附着和共同脱落制度已被观察到。结果表明，取决于初始扰动，可以在很宽的中心距（L/D [1.8，3.8]）范围内观察到再附着和共同脱落，这定义了双稳态流动范围。双稳态范围的下半部分的特征在于锁定现象，对于该锁定现象，当存在共脱落流动条件时，来自上游和下游气缸的旋涡脱落是同步的。
The flow around two circular cylinders in tandem arrangement with different diameters has been investigated numerically. The upstream to downstream cylinder diameter ratio was kept constant at a value of d/D=2/3 and the centre-to-centre distance was varied from 1.2D to 5D. The Reynolds number based on upstream cylinder diameter and free-stream velocity used in this study is equal to 200. Force coefficients and flow frequencies have been obtained from 2D fluid flow finite-element simulations. Single-wake shedding, reattachment and co-shedding regimes have been observed. The results show that, depending on initial perturbations, reattachment and co-shedding can be observed on a wide range of centre-to-centre distances (L/D∊[1.8, 3.8]), which defines the bi-stable flow range. The lower part of the bi-stable range is characterized by a lock-in phenomenon for which vortex-shedding from the upstream and downstream cylinders are synchronized when there are co-shedding flow conditions.