In practical engineering, the Reynolds number (Re) of box girder structure is usually very high (Re ≥ 10⁵), while most investigations of the flow around bluff bodies are concentrated on relatively lower Reynolds numbers (i.e., Re = 10³–10⁴). This paper presented a numerical study of the unsteady flow around two-dimensional rectangular cylinders under a Reynolds number of 6.85 × 10⁵ with different side ratios (R = b/h, width to height) ranging from 0.1 to 4.0. Three unsteady Reynolds-averaged Navier-Stokes (RANS) two-equation k-ε turbulence models (standard, RNG, and realizable) were adopted in the study. The realizable k-ε model was chosen because it was found to perform the best among three models in the main aerodynamic integral parameters. According to the distinctions of aerodynamic characteristics with different side ratios, three regimes were divided and discussed in detail. The distribution of surface pressure over cylinders, the wake parameters, and vorticity contours of the rectangular cylinders with different side ratios were discussed.

中文翻译：

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雷诺数为6.85×105时具有不同边比的二维矩形圆柱体绕流的非定常RANS建模

在实际工程中，雷诺数（重新箱梁结构的）通常是非常高的（重新 ≥10 ⁵），而周围钝体的流动的大部分研究集中在相对较低的雷诺数（即，回复 = 10 ³ -10 ⁴）。本文对二维矩形圆柱体的雷诺数为6.85×10 ⁵时的非定常流动进行了数值研究，其侧边比（R  =  b / h，宽度与高度）的范围为0.1到4.0。三个非稳态雷诺平均Navier-Stokes（RANS）二方程k-ε研究中采用了湍流模型（标准，RNG和可实现）。选择可实现的k-ε模型是因为发现它在主要空气动力学积分参数中在三个模型中表现最佳。根据不同边比的空气动力学特性的区别，对三种方案进行了划分和详细讨论。讨论了圆柱体表面压力的分布，尾流参数以及具有不同边长比的矩形圆柱体的涡度轮廓。