An Experimental Study Of Turbulent Structures And Fish Movement In Vertical Slot Fishway

With the rapid development of the social economy,human beings have more and more demand for water resources,and thus a large number of water conservancy projects have been established on rivers and lakes.These projects have brought enormous social and economic benefits,but at the same time they have also made fish The destruction of aquatic habitats has led to an increasingly prominent aquatic ecosystem,and the emergence of fish passes has protected aquatic organisms to a certain extent and alleviated the damage of the ecological environment.The effect of the fish on the road is not only related to the hydraulic characteristics of the fish pond,but also depends on the traceability of the fish.According to research data,there are still less than half of the fish passes that can be traced through the fish passes that have been built around the world!Therefore,it is of great practical significance to further study the hydraulic characteristics of fish passes based on fish migration habits,especially the mechanism of fish turbulence structure affecting fish migration.Trajectory of main flow,variation in the maximum velocity along flow direction,three-dimensional velocity profiles,turbulent wall jets,vortex characteristics,turbulent intensities,Reynolds stresses and their variations in flow rates as well as fish movement in vertical slot fishway were experimentally investigated.The experimentations were carried out in a large scale fishway model in the Laboratory of Port,Waterway and Coastal Engineering at Zhejiang University of Technology.The three planes of h/3,h/2 and 2h/3 flow depths were selected.The two vertical slit widths?10cm and 15cm??two typical flow rates?Q₁=20.62L/s and Q₂=30.75L/s?and17 cross-sections?x=5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85cm?were taken for each plane.The 23 measuring points were arranged along each cross-section.Three-dimensional velocity at each measuring point was measured by Acoustic Doppler Velocimeter?ADV?.Three-dimensional time-averaged velocity distributions,longitudinal and transverse turbulent intensity distributions as well as Reynolds stress distributions at different planes of flow depth in the pool of vertical slot fishway were analyzed.The empirical formula of main flow trajectory,relation of variation in the maximum velocity along flow direction,and semi-empirical and semi-theoretical formulas of three-dimensional velocity characteristics were proposed,and velocity vectors and rotation extent at each point in the flow field were given.And a comparison with the two vertical turbulence structures.In addition,swimming behaviors of target fish.in the fishway were observed by high speed photography based on the fish tests with implanted T-shaped tag.The relationship between the fish object and the turbulent structure of the vertical fish channel was analyzed.