In this paper, effects of nondimensional distance between two square cylinders on the dissipation characteristics of the complex flow are investigated. The viscosity entropy generation rates around two serial square cylinders and the lift coefficient are analyzed to fully reveal the statistical features of the flow dissipation. Numerical results mainly show that the major viscosity entropy generation rate appears in the shear intersection region of the main flow and local stationary vortex. The viscosity entropy generation rate increases with increasing nondimensional distance (S∗). The increasing slope of the viscosity entropy generation rate at a range of S∗≤2 is greater than that of 2≤S∗≤5. It is also found that the viscosity entropy generation rate is kept as a constant when the nondimensional distance S∗ is greater than 5. At S∗≥5, the effect of downstream square cylinder becomes negligible on the viscosity entropy generation rate. The fluctuating amplitude increases with increasing the nondimensional distance S∗. The high-frequency peak is ascribed to the strong vortex shedding around the downstream square cylinder, and the low-frequency peak is ascribed to the weak vortex shedding around the up square cylinder at S∗=1. Although our focus is mainly on the complex flow around two square cylinders, this work demonstrates the viscosity entropy generation rate with increasing nondimensional distance, which provides nice physical insight into understanding the local flow dissipation characteristics around the two serial square cylinders.

中文翻译：

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两方柱面无量纲距离对复杂流耗散特性的影响

本文研究了两个方形圆柱体之间的无量纲距离对复杂流耗散特性的影响。分析了两个串联方柱周围的黏熵产生率和升力系数，充分揭示了流动耗散的统计特征。数值结果主要表明主要黏熵产生率出现在主流与局部静涡的剪切交叉区域。粘度熵产生率随着无量纲距离的增加而增加（小号*）。在一定范围内粘度熵产生速率的斜率增加小号*≤2大于2≤小号*≤5. 还发现，当无量纲距离时，粘度熵产生率保持不变小号*大于 5。在小号*≥5，下游方圆柱体对粘度熵产生率的影响可以忽略不计。波动幅度随着无量纲距离的增加而增加小号*. 高频峰归因于下游方柱周围的强涡流，低频峰归因于上游方柱周围的弱涡流。小号*=1. 虽然我们的重点主要是围绕两个方形圆柱体的复杂流动，但这项工作展示了随着无量纲距离增加的粘性熵产生率，这为理解两个连续方形圆柱体周围的局部流动耗散特性提供了很好的物理洞察力。