The effects of a vertical slot fishway slope (with slope values from 1.5% to 6%) on a flow field are numerically investigated, using a re-normalization group – model. The distribution of the velocity, turbulence kinetic energy (), average energy dissipation rate per unit volume (), and vorticity for different slopes are systemically explored. The results indicate that, with an increase in slope, the appearance of downward flow in conjunction with an increase in vertical velocity results in three-dimensional flow characteristics. The recirculation region in , at a 6.0% slope, was 20.9% less than that at a 1.5% slope. Meanwhile, the flow velocity in the vertical slot region grew with increasing slope, which would limit the passage of fish with burst speed lower than the velocity in the vertical slot region. The and may locally exceed the threshold at larger slopes. Furthermore, vorticity distribution shows little variability with increasing slope, but may interfere with the equilibrium of the fish in the vertical slot region. In addition, the change in water level has little effect on the flow field, which is changed by the increase in slope. These findings can aid vertical slot fishway designs especially in terms of the efficiency of fish passage.

中文翻译：

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解读垂直槽鱼道中坡度变化对水流特性的影响

使用重归一化群模型对垂直槽鱼道坡度（坡度值从 1.5% 到 6%）对流场的影响进行了数值研究。系统地探讨了不同坡度的速度、湍流动能（）、单位体积平均能量耗散率（）和涡度的分布。结果表明，随着坡度的增加，向下流动的出现以及垂直速度的增加导致了三维流动特性。斜率 6.0% 时的再循环区域比 1.5% 斜率时的再循环区域小 20.9%。同时，垂直槽区域的流速随着坡度的增大而增大，这会限制突发速度低于垂直槽区域速度的鱼的通过。和 可能会在较大斜率处局部超过阈值。此外，随着坡度的增加，涡度分布几乎没有变化，但可能会干扰垂直槽区域中鱼的平衡。另外，水位的变化对流场影响不大，流场是通过坡度的增加而改变的。这些发现可以帮助垂直槽鱼道设计，特别是在鱼通过效率方面。