Numerical Simulation Study On Optimization Of Hydraulic Characteristics Of Vertical Slotted Fishway Tank

Fishway as an ecological compensation measure to assist retrospective fish to restore the migration path,the rationality of its pond structure layout affects the actual fish-passing effect.Taking the vertical slotted fishway of the Huangjinxia Water Control Project in the Hanjiang River Basin as an engineering example,and using the method of literature investigation,this paper collates and analyzes the basic data such as the hydrogeological conditions and the swimming ability of the fish object in the project area,and determines the range of hydraulic parameters of the fishway.The hydraulic numerical simulation of fishway tank chamber is carried out by using MIKE software,and the hydraulic characteristics of fishway tank chamber are further analyzed.The hydraulic characteristics of fishway tank chamber are optimized by means of narrow vertical seam width,adjusting guide angle,adding rectifier plate and so on,which provides data support for fishway engineering practice.The main conclusions are as follows:(1)The hydraulic numerical simulation results of the fishway tank chamber are basically consistent with the measured results of the fishway physical model test,and the data accuracy can meet the requirements of the analysis of the flow pattern and hydraulic characteristics in the fishway tank chamber.(2)Under different operating depths,the changes of the indoor flow pattern,the maximum velocity position distribution,the maximum velocity distribution along the pool chamber,the influence area of the backflow area(XR/L×YR/B)and the ratio of length to width XR/YR in the vertical slotted fishway pond with the same structure size are basically the same.That is,the distribution of flow structure in the fishway is basically not affected by the change of water depth.(3)The analysis results of the velocity distribution at the vertical seam of the fishway show that horizontally,the smaller the width of the vertical seam is,the more reasonable the velocity distribution is;longitudinally,the larger the width of the vertical seam is,the more uniform the velocity distribution at the vertical seam is.For the vertical slotted fishway of Huangjinxia Water Control Project,the vertical seam width b/B=0.175(b=0.35m)is the most reasonable.(4)Adjusting the guiding angle cannot prevent the mainstream sticking phenomenon of the fishway rest pool,and adding a rectifier plate can effectively prevent the mainstream sticking phenomenon of the fishway rest pool.Among them,at the distance between the right bank of the rest pool and the upstream pier,a rectifier plate with a length of 0.5m and a width of 0.2m is the most favorable.