竖缝式鱼道水力特性与鱼类运动特性相关性分析

竖缝式鱼道(Vertical Slot Fishway,VSF)作为一种协助上溯性鱼类恢复其洄游通道的生态补偿措施,受到广泛关注。其过鱼效果与VSF的水力特性和鱼类的游泳运动能力密切相关。因而,良好的VSF设计应保证池室内的水力特性与过鱼对象的游泳运动能力相适宜。本文选取上溯性鱼类鳙鱼和草鱼为研究对象,将VSF池室内水力因子空间分布与鱼类运动轨迹相叠加,定量分析了鳙鱼和草鱼在上溯过程中的运动特性、水力偏好以及鱼类运动轨迹与特定水力因子的相关程度。试验结果表明:在流量为0.135 m3/s的VSF池室内,两种鱼喜好在紊动能为0.02~0.035 m2/s2、流速为0.16~0.4 m/s、紊动耗散率为0.02~0.04 m2/s3、应变率为2~3.5 s-1的范围内运动。鳙鱼和草鱼在不同水力区域内的上溯时间与紊动能、流速相关性较大;水流流速矢量体现鱼的趋流特性,决定了鱼的上溯方向,而对于局部空间内鱼的游泳运动行为,紊动能可能是影响更直接的水力因子。

The correlation analysis between hydraulic characteristics of vertical slot fishway and fish movement characteristics

The vertical slot fishway (VSF), which can be viewed as an ecological compensation measure, plays a major role in enabling anadromous fish migration, which has received extensive attention. The fish-way passage efficiency is closely related to the VSF hydraulic characteristics and fish''s swimming capabili-ty. Therefore, an excellent VSF design should be suitable between the hydraulic characteristics of VSF and the fish''s swimming capability. Taking two anadromous fishes,Ctenopharyngodon idellus and Aristichthys no-bilis, as an example, this paper quantitatively analyzed the fishes'' movement characteristics, the preferred hydraulic ranges and the relevance of hydraulic factors and fish trajectories by combined the spatial distribu-tion of hydraulic factors with fish trajectories in VSF. The results show that the preferred ranges of turbu-lent kinetic energy, velocity, turbulent dissipation rate and strain rate are 0.02-0.035 m²/s², 0.16-0.4 m/s, 0.02-0.04 m²/s³ and 2-3.5 s^-1, respectively with the flow of 0.135 m³/s in VSF. The times swimming up-stream of the two fishes in different water areas are greatly associated with turbulent kinetic energy and ve-locity. In our study, the flow velocity, as a vector reflecting the rheotaxis of fish, determines the move-ment of fish,but their swimming behavior in local water area is mainly determined by turbulent kinetic en-ergy.