Abstract The three-dimensional flow around the four-cylinder and five-cylinder arrays are numerically studied at Re = 3900 by large eddy simulation (LES). By selecting eight spacing ratios (L/D = 2.0–7.0) and three incidence angles (α = 0°–45°), the influence of the center cylinder on the flow characteristics and interference effects of the four-cylinder array is discussed. Different spacing ratios can be divided into three categories with respect to flow regions of the multi-cylinder: small gap flow regime (L/D = 2.0–3.5), critical flow regime (L/D = 3.5–5.0) and large gap flow regime (L/D = 5.0–7.0). For cases with small spacing ratios, the influence of the center cylinder is very notable on the flow characteristics of the four-cylinder array. As the ratio increases, the influence of the center cylinder gradually decreases on the surrounding cylinders in the multi-cylinder array. On the other hand, the direction of the incoming flow also affects the flow characteristics of both four-cylinder and five-cylinder arrays. The development of the shear layer is strongly influenced by the center cylinder for the upstream cylinders at α = 45°. Boundary vortex flux components, flow characteristics and fluid force coefficients change significantly with adding the center cylinder for the four cylinders.

中文翻译：

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亚临界雷诺数下中心缸对四缸和五缸阵列流动特性的影响

摘要 通过大涡模拟(LES) 数值研究了在Re = 3900 时围绕四缸和五缸阵列的三维流动。通过选择八个间距比（L/D = 2.0–7.0）和三个入射角（α = 0°–45°），讨论了中心圆柱对四圆柱阵列流动特性和干涉效应的影响。不同的间距比根据多缸的流动区域可分为三类：小间隙流态（L/D=2.0-3.5）、临界流态（L/D=3.5-5.0）和大间隙流态制度（L/D = 5.0–7.0）。对于小间距比的情况，中心缸对四缸阵列的流动特性的影响非常显着。随着比例的增加，在多圆柱阵列中，中心圆柱对周围圆柱的影响逐渐减小。另一方面，来流方向也会影响四缸和五缸阵列的流动特性。剪切层的发展受到上游圆柱体的中心圆柱体的强烈影响，α = 45°。边界涡流分量、流动特性和流体力系数随着四个圆柱体的中心圆柱体的增加而发生显着变化。