The European eel population has undergone a significant decline in recruitment over the last 3–4 decades. Anthropogenic riverine barriers that disrupt the eel's life cycle when migrating upstream are contributory factors in this decline. The development of eel passage facilities is one of many attempts to mitigate this problem. In upstream passes, eels rely on a substrate in the base of the pass to assist their ascent by climbing and/or swimming. This study numerically evaluates, using computational fluid dynamics, the hydrodynamic characteristics of water flow on a studded substrate, under a range of installation angles and water flowrates. To assess and predict the efficiency of the pass, simulated flow field data were used to create pass-ability maps by comparing simulated velocity data with eel swimming capabilities. An 11° installation angle with a ramp flowrate of 1.12 × 10⁻³ m³/s per metre width was shown to be likely most suitable for 70 mm long eels, and could be used by eels with sizes up to 150 mm. The numerical study has also shown that under specific water flowrates, installation angles of 30° or more can make the water level fluctuate and splash out of the eel pass, resulting in potential inefficiency in ramp water supply, while posing additional challenges for eels ascending the pass.

中文翻译：

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镶嵌上游鳗鱼通道上水流的计算流体动力学模拟

在过去的 3-4 年中，欧洲鳗鱼种群的招募量显着下降。人为河流障碍在向上游迁移时破坏了鳗鱼的生命周期，是导致这种衰退的因素。鳗鱼通道设施的开发是缓解这一问题的众多尝试之一。在上游通道中，鳗鱼依靠通道底部的基质通过攀爬和/或游泳来帮助它们上升。本研究使用计算流体动力学，在一定范围的安装角度和水流量下，对镶钉基底上的水流的流体动力学特性进行了数值评估。为了评估和预测通过的效率，通过比较模拟速度数据与鳗鱼游泳能力，使用模拟流场数据来创建通过能力图。^-3  m ³ /s 每米宽度被证明可能最适合 70 mm 长的鳗鱼，并且可以用于尺寸高达 150 mm 的鳗鱼。数值研究还表明，在特定的水流量下，30°或更大的安装角度会使水位波动并溅出鳗鱼通道，从而导致坡道供水效率低下，同时对鳗鱼上浮带来额外挑战。经过。