Study On Diversion And Dissipation Of A Flood Retarding Project

River barrages are widely used in hydraulic engineering for its advantages of simple construction,less investment and more effective result.However,the head of the most river barrages is low and the reservoir area is large.Thus a low Froude number hydraulic jump may produce in the stilling basin.And its characteristics are the low dissipation of hydraulic jump and the volatile downstream flow,there will be serious erosion on downstream bank slope.Therefore,how to avoid the downstream bank slope’s scour in the low Froude number hydraulic jump is the key issue that the designers need to focus on.The purpose of the river barrage diversion engineering are to ensure that there are abundant water for the downstream industry and agriculture,and prevent the downstream water consuming units from using water unevenly during the two different seasons of wet and dry period.Therefore,scientific management should be taken by management units,which provides different operational mode for different water conditions,and ensure the water security of downstream area.The paper is based on an actual flood retarding project.Spilling sluice and diversion sluice are analyzed especially by FLUENT numerical simulation and physical model test on discharge capacity,flow pattern,water surface curve and velocity,analyzing dissipation effect and ensuring the safety of discharge and diversion.The main research results are as follows :(1)Consult and organize a large amount of literature on flood retarding project,focusing on the research on the downstream energy dissipation of low head barrage sluice and water diversion operation of diversion sluice.On the basis of previous research,sum up the research significance and current state research status at home and abroad.In addition,fundamental theories of turbulence simulation and numerical calculation are introduced in this paper.(2)For the spillway sluice,two kinds of design schemes are used on model test and numerical simulation.In the original design scheme,the discharge capacity is insufficient and unstable hydraulic jump is produced in the original design scheme,in which the flow of water in the stilling basin is volatile and dissipation ratio is low.Sluice gates are wider and downstream stilling basin is deeper and longer in optimized scheme to increase the discharge,improve the energy dissipation and reduced the downstream water surface fluctuation.Research shows good results.(3)For the diversion sluice part,operation mode on different water conditions is studied in particularly to ensure the downstream diversion discharge.The diversion operation of sluice gate in the design and check water level,winter with ice and not,plentiful water in June,flood occurred every two years,every three years and every five years,a total of eight kinds of conditions have been studied to guarantee the downstream water supply.The study not merely can provide a scientific basis for engineering design and operation management,but also can provide reference for the research of the similar problem.