突扩明渠边界层分离再附着流对鱼类游泳行为影响研究

Separated and reattaching flows of boundary layer, with complex nature of the turbulence，eddy motion and recirculating flow, is an important feature of open channel with sudden expansion, and the fishes in open channel will often encounter this flow. Fishes was found in the recirculation zone of spur dike and fishway pool by some test. Turbulence and eddy motion have a significant impact on fish behavior. A few studies show that some fish prefor to the wake flow of cylinder in order to reduce energy consumption. However, what is the principle of the effect of separated and reattaching flows of boundary layer in open channel with sudden expansion on fish swimming performance, has yet to see related research reports. This project intends to select freshwater fish in stream as the research object. The experiment on fish swimming performance will be carried out in flume, using the PIV to measure and analyse turbulence and eddy motion, using high-speed cameras and the animal behavioral analysis software to observe and analyse fish swimming performance. With superimposing on the hydrodynamic parameters and fish swimming performance parameters, we will gain the quantitative relationship between them by correlation analyzes, hydrodynamics sensitive parameters and the principle of the effect of separated and reattaching flows of boundary layer in open channel with sudden expansion on fish swimming performance. The research will help us insight the enffect of water flow on fish behavior,and will be reference for micro-habitat restoration for fish, the design of fishway,and the management of hydro scheduling.

突扩明渠边界层分离再附着流具有显著影响鱼类行为的紊流、漩涡运动和回流等复杂特征，明渠中的鱼类会经常遇到这种水流。鱼类在其回流区驻留现象客观存在，但这种复杂水流如何影响鱼类游泳行为，是否有与柱体绕流相同的影响规律，目前未见到相关研究报道，有待开展深入系统的研究。 为此，本课题拟针对喜流性淡水鱼类，开展不同明渠突扩结构和不同来流条件下的鱼类游泳行为水槽试验，采用PIV系统测量分析紊流和漩涡运动，采用高速摄像机和动物行为学分析软件分别观测和分析鱼类游泳行为，分析各种突扩明渠边界层分离再附着流中鱼类游泳行为特点，建立明渠突扩结构、来流流速和流场各水动力学参数对鱼类游泳行为的影响关系，识别影响鱼类游泳行为的敏感性参数，揭示明渠突扩边界层分离再附着流对鱼类游泳行为影响规律。研究成果将加深复杂水流对鱼类行为影响的认识，并对鱼类栖息地微观水流环境修复、过鱼设施设计和水电站枢纽调度管理等具有重要参考价值。

突扩明渠分离流具有显著影响鱼类行为的紊流、漩涡运动和回流等复杂特征，明渠中的鱼类会经常遇到这种水流。本课题针对喜流性淡水鱼类，开展突扩明渠中不同来流条件下的鱼类游泳行为水槽试验，采用高速摄像机和动物行为学分析软件分别观测和分析了鱼类游动轨迹、游动模式和游动范围，结合大涡模拟数学模型分析突扩明渠水流运动特性，揭示了各种突扩明渠分离再附着水流对鱼类游动行为影响规律。研究成果加深了复杂水流对鱼类行为影响的认识，对鱼类栖息地微观水流环境修复、过鱼设施设计和水电站枢纽调度管理等具有重要参考价值。