ABSTRACT

A pooled fishway is an artificial structure to improve the river flow connectivity and facilitate fish migration. Its conventional layout is characterized by straight weirs and suffers from limited passage rate. To improve its flow behaviors, an alternative design, featuring a V-shaped weir arrangement, is devised. CFD simulations are performed to examine its effects on the flow conditions. The governing geometrical parameters include weir angling, height, and spacing. Depending on weir arm angle, the flow is directed towards either the channel’s central part or the sidewalls, leading to both across- and along-channel differences in flow velocity and turbulent kinetic energy. This offers conducive zones for multiple fish species with distinct swimming preferences. For a given location in a pool, the cross-sectional velocity exhibits a cosine-type variation; a relationship is established to predict the maximum longitudinal velocity. The pressure distribution exhibits a similar pattern, with high-pressure areas residing upstream of the weir. A power law describes the relationship between the energy dissipation rate and unit discharge with an exponent at approximately 2/3. With an increase in either weir spacing or height, the energy dissipation rate declines. A change in weir angle shows however a negligible influence on it.

摘要

汇集的鱼道是一种人工结构，可以改善河流流量的连通性并促进鱼类迁移。其常规布局的特征是直的堰，并且具有受限的通过率。为了改善其流动性能，设计了具有V形堰结构的替代设计。执行CFD模拟以检查其对流动条件的影响。控制的几何参数包括堰的角度，高度和间距。根据堰臂角度的不同，流体会流向通道的中央部分或侧壁，导致通道速度和湍动能的跨通道和沿通道差异。这为具有多种游泳偏好的多种鱼类提供了有利区域。对于泳池中的给定位置，截面速度呈现余弦型变化。建立关系以预测最大纵向速度。压力分布表现出相似的模式，高压区位于堰的上游。幂定律描述了能量耗散率与单位放电之间的关系，指数约为2/3。随着堰间距或高度的增加，能量耗散率下降。然而，堰角的变化对它的影响可忽略不计。幂定律描述了能量耗散率与单位放电之间的关系，指数约为2/3。随着堰间距或高度的增加，能量耗散率下降。然而，堰角的变化对它的影响可忽略不计。幂定律描述了能量耗散率与单位放电之间的关系，指数约为2/3。随着堰间距或高度的增加，能量耗散率下降。然而，堰角的变化对它的影响可忽略不计。