鱼类坝下集群效应对水力学条件的响应规律研究

Research on the Response Pattern of Fish Schooling Effect on Hydraulic Conditions Under the Dam

拦河筑坝阻隔了鱼类洄游通道,鱼类具有天然的溯流习性,会感应到主流上溯,为进行产卵、索饵和洄游在过鱼季节聚集在坝下,产生鱼类坝下集群效应。鱼类的集群行为是鱼类行为学研究的重要内容。影响鱼类集群的三个重要水力学条件有流速、水深、紊动能,为研究鱼类坝下集群效应对水力学条件的响应规律,亟须建立集群分布规律与上述三个水力学因子的相关性。采用三维湍流模型对观测时所处运行工况的坝下流域进行了数值模拟,并用试验验证了数值模拟的合理性,使用观测仪器探测坝下四大家鱼分布规律,分析集群行为特点及其相关性。研究表明:当流速处于0.7～0.24 m/s之间时,鱼体数量与流速呈正线性相关,且四大家鱼集群最佳流速范围为0.060～0.12 m/s;当水深值处于2.4～3.9 m之间时,鱼群数量与水深呈正线性相关关系,鱼类集群适宜水深下限值为2.8 m;当紊动能值处于0～0.001 2kg·m^2/s^2之间时,鱼体数量与紊动能有明显的正线性相关关系,当紊动能值处于0.001 5～0.004 0 kg·m^2/s^2之间时,二者成负线性相关,且鱼类集群的平均紊动能适宜范围是0.000 50～0.001 2 kg·m^2/s^2。

Barrage and damming obstruct the migration of fish. Fish have a natural upstream habit and will be induced to the mainstream and migrate. In order to spawn,bait and migrate,fish cluster under the dam,thus generating the fish schooling effect. Fish schooling behavior is an important part of fish behavior research. Velocity,depth and turbulent energy are three important factors affecting fish schooling. In order to study the response pattern of fish schooling effect on the hydraulic characteristics under the dam,it is urgent for us to establish the correlation between the distribution rule of fish schooling and the above-mentioned three hydraulic factors. In this paper,the three-dimensional turbulence model is used to simulate the watershed under the dam in operating conditions during observation. The accuracy of the numerical simulation is validated by experiments. The distribution of the four major Chinese carps under the dam is observed by using observation instruments,and the relevance of schooling behavior and hydraulic characteristics are analysed. The results show that when the flow velocity is between 0.70 ～ 0.24 m/s,the number of fish body is positively correlated with velocity,and the optimum flow velocity range of the four fish groups is 0. 060 ～ 0. 12 m/s. When water depth is between 2. 4 ～ 3. 9 m,there is a positive linear relationship between the number of fish and water depth,and the lower limit of favorable depth of fish schooling is 2.8 m. When the turbulence energy is between 0 ～0.001 2 kg·m^2/s^2,there is a significant positive linear correlation between the number of fish and the turbulent energy,while performing a negative correlation when the turbulent energy ranges from 0.001 5 to 0.004 0 kg·m^2/s^2.And the optimum average turbulence energy of fish schooling is 0.000 50 ～ 0.001 2 kg · m^2/s^2.