Lip Bottom - Flow Dissipation Experimental Research And Numerical Simulation

The step-down bottom-flow dissipator is a new type of energy dissipator,it can better adapt to the high waterhead and single-width larger flow of water conservancy projects,with higher energy dissipation rate and eliminating fogging on the traditional bottom flow dissipation.Compared to the traditional dissipater its most important feature is that it can reduce the plunge pool hydraulics indicators.Currently,our country has appeared the actual water conservancy project object(such as the under construction Xiangjiaba Hydropower Station and Jin’anqiao Hydropower Station)applied the step-down bottomflow dissipator,the experts have produced some of the more basic research and results,such as a plunge pool hydraulic characteristics influencing factors,but do not hace systematic and numerical simulation of the step-down bottom-flow dissipator is relatively less.This article based on the National Natural Fund Project(5169008):Study on hydraulic characteristics of the flow structure in the step-down bottom-flow dissipator,analyed dissipation mechanism and flow structure of step-down bottom-flow dissipator. Adopting hydraulic methods to make a a physical model test,hydraulic indicators are observed.And the corresponding model calculation results are obtained by numerical simulation,by comparison,the two results reach basic agreement. Finally,through numerical simulation,the paper studied affect on hydraulic indicators by changing stilling basin body,and drawed some conclusions for the corresponding physical model tests to verify the numerical simulation conclusions. The relevant conclusions are as follows.Anti-arc radius of the end of chute has a greater impact on the hydraulic characteristics of stilling basin.As the anti-arc radius decreases,the centrifugal force will increase,the flow kinetic energy will decrease,the range is also reduced,making the hydraulics indicators increasing.Slope size of the step-down face has a greater impact on the hydraulic characteristics of stilling basin.The junction position of step-down with bottom is unchanged,with the slope size of the step-down decreasing,the energy dissipation water below the mainstream increased,enhancing role of energy dissipation,making the hydraulics indicators decreasing. The results of numerical calculation analysis shows that simply change the tail slope without changing its depth has not a greater impact on the number of energy dissipation water in the stilling basin,making a little impact on the hydraulics indicators.