Abstract:

The vertical slit fishway has the characteristics of good flow conditions of water, clear location of the reflux zone, and strong adaptability to changes in upstream and downstream water levels. It is currently a high efficient and widely used fish passing engineering facility. In order to increase the effectiveness of fish migration in the research area, according to regulatory requirements, three types of fishway tank compartments were preliminarily designed, and numerical simulation methods were used to explore the impact of changes in baffle types on the flow structure of water of the tank compartments at a constant depth of 2 meters both upstream and downstream. The baffle type was optimized by analyzing the water flow pattern inside the pool, the velocity distribution at the vertical joints, and the energy dissipation effect. By changing the size of the second type of baffle, the width of the vertical joint was reduced from 0.6 m to 0.5 m. Under the premise of flow pattern of good water in the tank and flow velocity at the vertical joint, the maximum flow velocity near the vertical joint was reduced to less than the design flow velocity of 1.2 m/s; and the flow capacity of the optimized body under different conditions of equal water depth was calculated. When the water depth changed between 0.5 m and 2.0 m, the flow capacity of the fishway was between 0.236 m³/s and 0.951 m³/s. The flow pattern of good water inside the pool and the rationality of the velocity distribution at the vertical joints provided a good channel for the trace back of most fish in the study area, and the flow capacity at different water depths provided a reference for the operation and scheduling of the fishway.

Key words: hydraulics, vertical slit fishway, optimization, numerical simulation, analysis