Abstract

Many efforts have been dedicated to examining the flow characteristics around a pair of cylinders. Despite the straightforward geometry, the flow dynamics around a cylinder prove to be intricate. The practical applications of this phenomenon extend across various engineering domains, including oil and gas transmission lines, heat exchangers, pipelines, and the construction of successive skyscrapers. The current investigation delves into the examination of the critical distance ratio, fluctuating velocity, flow pattern, and drag surrounding two sequential circular and square cylinders. The governing equations are solved using the finite volume method (FVM). For momentum, turbulent kinetic energy, and turbulent dissipation rate equations, the upwind second-order discretization is used. The findings, acquired at a Reynolds number of 32,000 for distance ratios ranging from 0.25 to 10, are then compared with those from single-cylinder cases. The results highlight the significant influence of both geometry and the distance between cylinders on the observed flow patterns. The critical distance ratio is obtained as \(s_{c}\)  = 2 and 2.5 for the case of two sequential circular and square cylinders, respectively, while for the case of combined circular and square cylinders, it is calculated as \(s_{c}\)  = 3. The non-dimensional fluctuating velocity decreases by 7%, 26%, and 38% in the case of two sequential circular cylinders with distance ratios of S* = 1, 2, and 3 at the first station, respectively, compared to a single circular cylinder. The drag coefficient is 50% lower in the two sequential circular and square cylinders case compared to the single square cylinder.

中文翻译：

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两个具有圆形和方形横截面的连续圆柱体周围流动特性的数值研究

摘要

许多努力致力于检查一对气缸周围的流动特性。尽管几何形状简单，但圆柱体周围的流动动力学被证明是复杂的。这种现象的实际应用遍及各个工程领域，包括石油和天然气传输线、热交换器、管道以及连续的摩天大楼的建设。当前的研究深入研究了两个连续的圆形和方形圆柱体周围的临界距离比、脉动速度、流动模式和阻力。使用有限体积法 (FVM) 求解控制方程。对于动量、湍流动能和湍流耗散率方程，使用迎风二阶离散化。研究结果是在雷诺数为 32,000、距离比范围为 0.25 至 10 时获得的，然后与单缸情况下的结果进行比较。结果强调了几何形状和圆柱体之间的距离对观察到的流动模式的显着影响。对于两个连续的圆形和方形圆柱体的情况，临界距离比分别为\(s_{c}\)  = 2和2.5，而对于组合的圆形和方形圆柱体的情况，计算为\(s_ {c}\) = 3。首站距离比为S * = 1、2、3 的两个连续圆柱体情况下，无量纲脉动速度分别降低7%、26%、38% ，分别与单个圆柱体相比。与单个方筒相比，两个连续的圆形和方筒情况下的阻力系数降低了 50%。