Study On The Body Type Optimization Of Differential-type End Sill Under Energy Dissipation By Hydraulic Jump

High dam discharge flow usually has high velocity,large discharge per unit width and extremely complex hydraulic characteristics,which poses a great threat to downstream energy dissipation and erosion structures.Moreover,it increases the difficulty of the energy dissipation design.Hubs'(especially for the high dams)hydraulics problems of the energy dissipation and erosion control has always been a heated issue in engineering construction and scientific research.Therefore,reasonable and correct choice of energy dissipation measures is the criticalfactorto determine the safety and comprehensive benefitsof drainage structures and even the whole hub.Energy dissipation by hydraulic jump,as a basic form of energy dissipation building,It is more common in practical engineering.The main types of energy dissipation by hydraulic jump are stilling basin,stilling bucket,comprehensive stilling basin and so on.There are three types of baffle wall style:continuous,dental formula and differential-type,in which the differential-type end sill has many advantages,such as energy dissipation and sand washing,improving the flow pattern of the outlet,reducing the erosion of the river bed scour,and having a good adaptability to the apron.Therefore,the study of the energy dissipation of the differential-type end sill of the energy dissipation by hydraulic jump has a certain theory and the value of engineering use.In this paper,the hydraulic characteristics of the end till are studied on the basis of the stilling basin of flood discharge and desilting hole in a power station in Pakistan.Theoretical analysis,model test and numerical simulation and analysis are combined in this research.The main achievements of the paper are as follows:(1)The design principle of differential-type end sill is summarized.The problems existing in the application of differential-type end sill and the corresponding measures mastered,which lay a theoretical foundation for the study and analysis of the hydraulic characteristics of the differential-type end sill.(2)The original optimization scheme is modeled and the corresponding numerical simulation is carried out.The reliability of the numerical simulation is verified by comparing the calculated results with the model test's results.Simultaneously,the existing problems of the original optimization scheme are analyzed,the best scheme design of the differential-type end sill is presented according to the design criterion of the somatotype and layout.(3)Under the conditions of the sediment ejection level,the numerical analysis of the hydraulic characteristics of the differential-type end sill under different schemes is carried out.Combined with the basic theory of hydraulic mechanics and the control condition of the differential-type end sill,it is improved the best recommendation after repeated improvement of the somatotype,and the model of the program experimental study.The results show that this type of differential-type end sill can meet the applicable conditions.The water jump in stilling basin is full and stable,and the upstream and downstream reaches of the bucket are connected well,which indicates that the energy dissipation effect is good.For the design and construction the best project is proposed.