基于多重水力学因子的竖缝式鱼道中鱼类上溯轨迹模拟

The simulation of fish migratory trajectory in a vertical slot fishway based on multihydraulic indices

为探讨鱼类在竖缝式鱼道上溯过程中对各种水力学因子的适应性特征,对其上溯轨迹的模拟研究十分必要。本文采用数值模拟技术对竖缝式鱼道中的流场、湍流动能场及湍动耗散率场进行计算,并根据鱼类对各种水力学因子的偏爱程度赋以相应的权重,从而模拟分析以上3种水力学因子综合影响下,鱼类个体在竖缝式鱼道中的上溯轨迹,并采用已有的实验研究成果对模拟结果进行对比校准。结果表明:鱼道中湍流动能场的分布结构是影响鱼类轨迹最为重要的水力学因子,鱼类上溯轨迹总是出现在某一湍流动能阙值附近;鱼类的趋流特性虽然影响较小,但不可忽略,它在鱼类洄游过程中起着重要的导向性作用,是鱼类能够不断上溯的关键因子;湍动耗散率对鱼类上溯的影响非常有限,可以考虑将其忽略。

To explore the fish adaptability under various hydraulic factors during the process of fish tracing in a vertical slot fishway, it is necessary to simulate the fish migratory trajectory. In this study, a numerical model was used to calculate the flow field and the field of turbulentkinetic energy and its dissipation rate in a vertical slot fishway. An influence coefficient for each hydraulic factor was endowed by the degree of fish preference on them. With this method, themigratory trajectory of a fish was modeled and adjusted by results from previous laboratory experiment. The results showed that the field structure of turbulent kinetic energy influenced the fish trajectory most profoundly since most the tracing points appeared nearby a threshold value ofturbulent kinetic energy. The influence of centripetal velocity was limited but not negligible, because it is a key factor in the process of continuous fish traceability. The influence of the turbulence dissipation rate could be negligible.