Three-dimensional Numerical Simulation Of Turbulent Structure Of Fishway Chamber With Bottom Holes And Vertical Slot

After the development of fish passage in the 20 th and early 21 st centuries,the design of fish passage body shape has been generally mature.With the deepening of people’s understanding of fish habits and turbulence characteristics in fish passages,some unappreciated problems are gradually exposed,and it is evident that the research on fish passages still needs to be explored in depth.In this paper,the turbulence structure of the pool chamber of the bottom-hole vertical slit combination fishway is analyzed by using the physical model test method,and the hydraulic characteristics of the pool chamber of the bottom-hole vertical slit combination fishway are investigated by using the numerical simulation method when the bottom slope is stepped and sloped.The following main conclusions were obtained:(1)In the fish passage partition for the same side of the arrangement,the flow of water by the vertical seam and orifice control,the orifice at the jet is dispersion type,while the formation of two small eddies on both sides of the orifice,the pool room surface mainstream area flow pattern is linear,the pool room in the upstream against the vertical seam mainstream water flow formed a clockwise vortex;in the heterogeneous side of the arrangement,the upstream orifice mainstream and the vertical seam mainstream combined flow,the center of the pool room there is a counterclockwise large vortex,the pool room surface mainstream area flow pattern is “L” type,the flow pattern is better,the pool room energy dissipation is more adequate.(2)From the pool room orifice center and vertical seam center longitudinal flow velocity distribution along the longitudinal and pool room in different cross-sections on the orifice centerline position at the longitudinal,transverse,vertical flow velocity distribution can be seen,in the same side and different side of the arrangement,in the pool room upstream orifice and vertical seam position of the back end of the existence of a water acceleration region;pool room upstream cross-section of the transverse flow velocity trend is “small at both ends,large in the middle”;by the pool room in the downstream reflux area,the right bank will be congested;pool room cross-section flow velocity distribution law: vertical flow velocity < transverse flow velocity < longitudinal flow velocity.(3)The distribution of turbulence intensity along the lateral direction at the centerline position of the orifice on different cross-sections of the pool chamber can be seen that the turbulence intensity at the mainstream position of the orifice and the mainstream position of the vertical seam on the upstream cross-section of the pool chamber is the largest under the same side arrangement;the turbulence intensity at the right-hand position of the orifice on the upstream cross-section of the pool chamber is the largest under the different side arrangement,and the turbulence intensity on the left and right banks is smaller;under the same side and different side arrangement,the turbulence intensity of the pool chamber The longitudinal turbulence intensity in the longitudinal section of the vertical seam center of the pool chamber varies in the same trend,and the longitudinal turbulence intensity in the longitudinal section of the vertical seam center of the pool chamber in the heterolateral arrangement is higher than that in the homolateral arrangement.(4)Under the same side arrangement of fishway bulkhead,the main flow trajectory of the bottom hole vertical slit combined fishway chamber is similar to “H” type;the turbulent kinetic energy distribution pattern of each section under different water depths is basically the same,and the high turbulent kinetic energy is at the combined flow of the main flow of the orifice and the vertical slit,at the dispersion of the main flow of the orifice and the downstream bulkhead area of the chamber;the main flow trajectory of the chamber under the different side arrangement is similar to “L” type,and the return flow area of the chamber is more similar to the circular type;the comparison shows that the energy dissipation effect of the stepped fishway chamber is better than the slope type,and the energy dissipation effect of the chamber under the different side arrangement is better than the same side arrangement.