Drop The Underflow Energy Dissipation Work Flow And Vortex, The Characteristics Of Research

In recent years,along with the development of the water resources in western and the start of some high dam project,the high waterhead,high flow,naarrow valley and deep tail water has been the most important problem of the the leaking water engineering, the energy dissipation of traditional form hasn’t fulfiled the need of te engineering.Therefore the problem of the energy dissipation about flood discharge turns into particularly important,these factors prompted several energy dissipater of new form.At the same time of introducing traditional energy dissipater in this paper,and it recommend the using conditions and insufficient of each one.And come up with several energy dissipation of new form on the basis above,and introduce the step-down bottom energy dissipater to be researched.since the late1990s, as the environmental protection consciousness of people rise increasingly,the discharge performance of the dam is not just to ensure safety of the buildings,but set higher requirements to the protection of the downsteam ecological.the energy dissipation by trajectory jet is commonly used in the flood discharge of high dam,but it would result in downstream silting and forceful atomized rain,these problems would strongly damage the soil conservation and entironmem of downsteam.The solution of the problem about hydraulics and entironment caused by the flow with high speed and flux would be one of the key technology about hydroelectric development.The step-down bottom energy dissipater can adapt various kinds of waterhead and different geological conditions,morever it has other advantages of low velocity near the bottom,less volatile tail water and1ow degree atomization.This new energy dissipater had put into use successfully in JinAnQiao and Xiangjiaba hydroelectric,but it still exists some problem like low-pressure area after the step and scour to the stilling basin or the face ot step,these problems affected by the vortex after the step.At present the research of the vortex after step is nearly blank,it is the springboard and major objective of this paper.This paper bases on the Natural Science Fund Item Of China(51169008)《Experimental investigation and numerical simulation about the vortex after step of the step-down bottom energy dissipater》.Use the method of hydraulics experiment,observe and record the data in the stilling pool,emphasize on the research of the Under submerged bottom flow pattern,it includes the research of waterline,the velocity near the bottom,the pressure on the base board.Based on the research above,emphasize on the analysis about the area of roll swirl after step. Calculate the computational domain under different working conditions by numerical simulation.Get the conclusion like the distribution of characteristic velovity and pressure about vortex after step,and the change of the vortex under different boundary conditions, contrast the test data and the results of the numerical simulation,adequately checked the method of numerical simulation,it is viable and exact to deal with the practical hydraulics problem.