| Sluice is a low-headed aquatic building built along the river or ditch,which plays an important role in flood control,navigation,irrigation,and drainage.As an inevitable part of the natural river and artificial river channels,the hydraulic characteristics of curved forked river are very complicated,which not only affects the stability of the flow field in river,but also easily cause hidden dangers of the surrounding structures.Therefore,research on the hydraulic characteristics of connecting the sluice of the corner forks has certain guiding significance in theory and practice.The upstream connecting section of Tongcheng Sluice is located at the mouth of Sancha River,with a width of 100m and it is a large Ⅱ sluice with 11 sluice holes.By taking Tongcheng sluice project as the research object,this paper used NX11.0 modeling software and Fluent calculation software to numerically simulate the inflow state of Tongcheng sluice.The results of the numerical simulation calculation show that when the upstream is in diversion conditions,due to the effect of diversion and of inflow a large angle bias caused in front of the sluice.There was a large anount of flow accumulates on the right side of the sluice and a large range of low-speed area in front of the sluice,which makes the flow in front of the disordered.Additionally,the diversion scours the concave bank of the three branches of the river and also causes the spiral circulation on the convex bank,which causes great problems on the safety and stability of the whole project.When the upstream was under the confluence condition,the inflow was smooth and the flow pattern was ideal.In order to improve the poor flow pattern in front of the sluice under the diversion condition,on the basis of the original scheme,the flow pattern in front of the sluice is improved by changing the geometric layout parameters of the wing wall,setting up engineering measures both in front of the sluice at the bifurcation of the bend.Through comparative study and analysis,it can be found that:firstly,changing the length and shape of the right wing wall of the sluice properly can reduce the influence of the water flow dead angle on the right side of the sluice and the excessive angle between the inlet velocity vector and the pier direction caused by the diversion in front of the sluice.Secondly,setting the sill in front of the sluice can improve the velocity uniformity of the entrance section of the sluice,and the overall optimization effect was similar to changing the geometric parameters of the wing wall.Thirdly,riprap was set at the bend,which can not only reduce the drag effect of diversion,but also large angle bias current in front of the sluice;Additionally the spiral circulation caused by diversion can also be alleviated,along with the erosion of the concave bank of Sancha River,thus the whole project can be protected more effectively.Through the comprehensive evaluation index,it is found that when a riprap with the length of 70m,width of 1.5m and height of 2.0m was arranged at the bend,compared with other schemes,riprap at the bend has the best rectification effect which can effectively improve the inflow pattern of the sluice.On the basis of numerical simulation calculations,use the overall normal hydraulic model of the ratio of 1:60.Through the physical model test of the Tongcheng Sluice’s water inlet,and combined with the typical solution of numerical simulation,the actual measurement data of the water intake dance is consistent with the consistency of the numerical simulation results.At the same time,the physical model test also shows that the setting stone throwing at the curve can effectively improve the inflow of the sluice.The research results of this paper can provide some suggestions and improvement measures for Tongcheng sluice project,as well as a good inflow conditions for Tongcheng sluice,thus the chaotic flow pattern in front of the sluice can be improved,ensuring the safety of the sluice and improving the operation safety and stability of the whole project. |
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