Flow past four side-by-side identical square cylinders arranged normal to the flow have been found to show interesting and important flow features which are very difficult to get through experiments. Lattice Boltzmann method (LBM) is used for numerical simulations of two-dimensional (2D) flow around four side-by-side arranged cylinders. In this study, the Reynolds number (Re) is chosen to be 60, 80, 100, 120 and 140 and the spacing ratio g* (= g/D, where D is the size of cylinder and g is the distance between the cylinders) is set at 0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5 and 4. Based on the flow characteristics, seven distinct and unique flow regimes are identified for different ranges of Re and g*. Physical features of each flow regime such as wake structures, vortex dynamics, gap flow behavior, time histories of lift coefficients, shedding frequencies and hydrodynamic forces are thoroughly discussed. The Reynolds numbers strongly affect the flow, especially at 0 ≤ g* ≤ 2, in terms of vortex-shedding frequency. A significant secondary frequency is also found other than the primary frequency in the base-bleed and flip-flopping flow regimes. It is observed that for g* ≥ 2.5 primary shedding frequency strongly affects the flow dynamics and the mutual interaction of the wakes behind the cylinders decreases with an increase in the Reynolds number. The Strouhal value is same for the outer and inner cylinders in inphase–antiphase weak interaction flow regime and different for base-bleed and flip-flopping flow regimes. In inphase asynchronous weak interaction flow regime, the Strouhal number is same for all four cylinders.

已经发现流过垂直于流的并排布置的四个相同的方形圆柱体的流显示出有趣且重要的流特征，这些特征很难通过实验获得。格子Boltzmann方法（LBM）用于围绕四个并排布置的圆柱体的二维（2D）流动的数值模拟。在这项研究中，雷诺数（Re）选择为60、80、100、120和140，间距比g *（=  g / D，其中D是圆柱体的大小，g是气瓶之间的距离）设置为0、0.25、0.5、0.75、1、1.25、1.5、1.75、2、2.5、3、3.5和4.基于流动特性，确定了七个独特的流动方式对于Re和g *的不同范围。详尽讨论了每种流动状态的物理特征，例如尾流结构，涡旋动力学，间隙流动行为，升力系数的时间历史，脱落频率和流体动力。雷诺数强烈影响的流动，特别是在0≤ 克*≤2，在涡流脱落频率方面。除了基本泄放和触发器流动模式中的主频率外，还发现了一个重要的辅助频率。观察到对于g*≥2.5的主要脱落频率会强烈影响流动动力学，并且随着雷诺数的增加，圆柱后面的尾流的相互影响会降低。在同相-反相弱相互作用流态下，外圆柱体和内圆柱体的Strouhal值相同，而对于底流和触发器流态，Strouhal值则不同。在同相异步弱相互作用流态下，所有四个气缸的斯特劳哈尔数均相同。