Horizontal bar racks are successfully used to protect downstream migrating fish and guide them to a bypass at a number of hydropower plants. However, there is no systematic study available on the hydraulic performance of such fish guidance structures. To fill this research gap, we experimentally investigated scale effects and hydraulic head losses of horizontal bar racks. The study involves two main rack angles, two bar shapes and depths, and three bar spacings as primary parameters characterizing the structure investigated as well as top, top & bottom, and bottom overlays as secondary parameters. The bar spacing was the most important factor determining the flow–rack interactions, followed by the rack angle, bar shape and depth, respectively. The overlay positions at the rack resulted in three distinct flow–rack interactions. A new head loss prediction formula was developed and compared with literature data. Recommendations for the optimum and economic rack design are given.

中文翻译：

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单杠导鱼结构的试验研究

水平杆架已成功用于保护下游洄游鱼类，并将它们引导至多个水力发电厂的旁路。然而，没有关于此类鱼引导结构的水力性能的系统研究。为了填补这一研究空白，我们通过实验研究了单杠货架的规模效应和水头损失。该研究涉及两个主机架角度、两个钢筋形状和深度以及三个钢筋间距作为表征所研究结构的主要参数，以及作为次要参数的顶部、顶部和底部以及底部覆盖层。杆间距是决定流动-机架相互作用的最重要因素，其次是机架角度、杆形状和深度。架子上的重叠位置导致了三种不同的流-架相互作用。开发了一种新的水头损失预测公式，并与文献数据进行了比较。给出了最佳和经济机架设计的建议。