Research on the Influence of Vertical Joint Position on the Hydraulic Characteristics of Different Side Vertical Joint Fishway.

The opposite side vertical joint fishway has the characteristics of better adaptation to water level changes, obvious energy dissipation effect and better flow pattern of water. According to the design guidelines, the fish passage in the study area is designed in body shape. In this paper, the effect of different vertical slit positions on the flow structure of the chamber is investigated by numerical simulation, including the hydraulic characteristics of the main flow area, the hydraulic characteristics of the return flow area and the flow velocity distribution of the vertical slit position, and the vertical slit position of the fish passage suitable for the fish in the study area is analyzed. The simulation results show that: the vertical slit position has almost no effect on the maximum flow velocity in the pool chamber of the opposite side vertical slit, and has less effect on the change of the maximum flow velocity along the main flow area. As the center of the vertical slit gradually approaches the center of the pool chamber, the decay of the maximum flow velocity along the main flow area takes the lead in gradually becoming larger and then tends to saturate. Most of the flow velocity in the return area of the upper left part of the main flow area gradually decreases and then increases, and most of the flow velocity in the return area of the lower right part gradually increases. The area ratio of the two sides of the reflux zone gradually decreases. The vertical slit position on the pool room mainstream area flow pattern and the flow velocity distribution of the return area has a significant impact, when 0.23≤l/B≤0.40, the pool room flow pattern is the best; when l/B≥0.37, the mainstream area along the maximum flow decay rate tends to saturate, when 0.37≤l/B≤0.40, the maximum turbulent kinetic energy in the pool room at l/B =0.40 minimum, and the area of the return area on the left and right sides. Therefore, when l/B=0.40, the migratory effect of semi-migratory fish in the study area can be significantly improved. The maximum variation of turbulent energy in the pool is between 0.074 and 0.116 m²/s² when the vertical slit is located at 0.13-0.50 of the width of the pool chamber from the side wall, and the flow pattern in the pool is the best when the vertical slit is located at 0.23-0.40 of the width of the pool chamber, which can significantly improve the migratory effect of semimigratory fish in the study area. The results of the study clarify the influence of the center position of the vertical joints on the water flow structure of the pool chamber and provide a reference for the subsequent design and research work of other related fish passage projects. [ABSTRACT FROM AUTHOR]