Abstract Wind tunnel experiments on flow interference of adjacent (spacing ratio P/B ​= ​1.75) twin square cylinders in various attack angles α were conducted at a Reynolds number of 8.0 ​× ​104 considering both horizontal and diagonal arrangements of models. Investigations on the mean and fluctuating aerodynamic force coefficients, mean and fluctuating wind pressure coefficients, spanwise correlations, power spectrum densities (PSD) of lift, and Strouhal numbers of two cylinders, as well as the inter-cylinder correlations between them, are presented. The results show that the aerodynamic characteristics of two diagonal cylinders differ significantly from those of horizontal ones. Compared with the single-cylinder, the pressure distributions on adjacent cylinders are dramatically changed, leading to the negative drag, attractive lift, or repulsive lift on the downstream cylinder. At small α, diagonal cylinders present stronger mean drag and higher fluctuating forces than horizontal cylinders do. Besides, a stronger spanwise correlation is found for the diagonal ones. The vortex shedding pattern can be divided into four stages for the horizontal arrangement and six for the diagonal case. PSD curves and Strouhal numbers are similar between two cylinders for both arrangements, suggesting that the two closely spaced cylinders act like one bluff body in the vortex shedding.

中文翻译：

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不同排列的两个紧密排列的方柱体的气动特性

摘要 考虑模型的水平和对角排列，在雷诺数8.0×104下，对相邻（间距比P/B = 1.75）双方圆柱体在不同攻角α下的流动干涉进行风洞实验。介绍了对平均和波动气动力系数、平均和波动风压系数、展向相关性、升力功率谱密度 (PSD) 和两个气缸的 Strouhal 数以及它们之间的气缸间相关性的研究。结果表明，两个对角圆柱体的气动特性与水平圆柱体的气动特性存在显着差异。与单缸相比，相邻缸上的压力分布发生了显着变化，导致负阻力、吸引升力、或下游气缸上的排斥升力。在较小的 α 下，对角圆柱比水平圆柱呈现出更强的平均阻力和更高的波动力。此外，对角线的展向相关性更强。涡旋脱落模式可分为水平排列的四个阶段和对角排列的六个阶段。两种排列的两个圆柱体之间的 PSD 曲线和 Strouhal 数相似，这表明两个紧密间隔的圆柱体在涡旋脱落中就像一个钝体。涡旋脱落模式可分为水平排列的四个阶段和对角排列的六个阶段。两种排列的两个圆柱体之间的 PSD 曲线和 Strouhal 数相似，这表明两个紧密间隔的圆柱体在涡旋脱落中就像一个钝体。涡旋脱落模式可分为水平排列的四个阶段和对角排列的六个阶段。两种排列的两个圆柱体之间的 PSD 曲线和 Strouhal 数相似，这表明两个紧密间隔的圆柱体在涡旋脱落中就像一个钝体。