基于流场-轨迹耦合的鱼道内鱼类运动路径模拟研究

The fishway, which can be viewed as an ecological compensation measure, plays a major role in enabling fish migration. The simulation of fish’ movement process in fishway is one of the hot researches recently. Based on Eulerian-Lagrangian simulation method, how to further coupling fish trajectories to realize dynamic movement simulation of fish in fishway were the main problems. Taking Schizothorax oconnor as an example, flow field information will be studied using flow field measurement and simulating, fish movement will be quantified using video recording and RFID in Zangmu fishway, and the elements of fish upstream movement will be parsed. Specifically, the Eulerian fluid dynamics model, the stimulus-response model of individual fish considering the fitness principle and the Lagrangian model considering particle tracking algorithm for fish trajectory will be established, preferred ranges of different hydraulic factors and the most important hydraulic factor can be recognized , and the three models will form Eulerian-Lagrangian-stimulus-response coupling model. Finally, multiple fish trajectories combining with the process of fish upstream movement by field monitoring will be simulated, the coupling model are calibrated and optimized, which will confirm the practicability of the model, and reveal the response mechanism between upstream movement of fish and the hydraulic characteristic in fishway. The research results help to reveal the interdisciplinary development of hydraulics and fish behavior, which has important scientific significance to help the migration route of fish and the references effects for improving the fishway design.

鱼道是协助鱼类恢复其洄游通道的生态补偿措施。鱼道内鱼的运动过程模拟是目前研究的热点之一。如何基于欧拉-拉格朗日的模拟方法，进一步耦合鱼类轨迹，是实现鱼道内鱼类运动模拟的主要技术瓶颈。本项目依托藏木鱼道，以异齿裂腹鱼为研究对象，通过现场测量和数值模拟获取鱼道流场信息，结合现场过鱼效果监测，采用视频记录和射频识别定量鱼的运动轨迹，解析鱼的上溯运动要素；通过基于欧拉的流体动力学模型、基于适宜度原理的个体鱼刺激-响应模型和基于拉格朗日质点跟踪算法的鱼体运动轨迹模型，获取鱼类偏好的水力范围及关键水力因子，构建基于欧拉-拉格朗日-刺激响应鱼类运动模型；结合对鱼道现场鱼类的上溯过程解析，模拟多条鱼的运动轨迹验证并优化模型，证实模型的实用性，以期揭示鱼类运动对鱼道水力特征的响应机制。研究成果对水力学和鱼类行为学的交叉学科发展具有重要的科学意义，为恢复鱼类的洄游通道以及鱼道设计、改进提供科学依据。

本项目通过现场测量和数值模拟获取鱼道流场信息，将流场水力空间分布与鱼道内鱼的运动轨迹相耦合，量化了鱼类上溯运动过程中偏好的水力范围，鳙鱼更倾向于在平均紊动能为0.02～0.043m2/s2的区域上溯运动，鱼更喜欢在流速为0.15～0.45m/s的范围内运动，鱼更喜欢在应变率为紊动耗散率为 0.02～0.065 m2/s3的范围内运动，鱼更喜欢在应变率为2～7 s-1的范围内运动。考虑鱼道内鱼类上溯的随机性，提出了鱼类对水流刺激的感知范围函数，结合个体鱼的运动规则，构建基于个体鱼刺激-响应模型；基于鱼类偏好的水力范围及关键水力因子，构建基于欧拉-拉格朗日-刺激响应鱼类运动模型；通过模拟多条鱼的运动轨迹验证并优化了模型，证实了模型的实用性，揭示了鱼类运动对鱼道水力特征的响应机制。研究成果为恢复鱼类的洄游通道、鱼道设计、改进提供了支撑。