Numerical Simulation For Stepped Spillway Based On 3D VOF Model

Discharge structures must be set in water conservancies.In order to ensure dams safety,the stepped spillway is a common drainage building,it is planned for the flood which can not be accommodated.Not only sufficient discharge capacity should be needed in the stepped spillway,but also their own safety and the proper connection between original river and discharge flow should be ensured during the work.Located in a high altitude cold area of western China,Qinghai Province,the rich hydropower resources can be guaranteed.There is a very important significance for the research of hydraulic characteristics of stepped spillway to prevent the cavitation and cavitation erosion in the cold area of high altitude.In this paper,VOF method combining the RNG k-e turbulence model and one-way fluid free tracing interface is used to conduct a three-dimensional numerical simulation study on the stepped spillway.The development process of RNG k-e turbulence model is summarized.The application status of numerical simulation technology is introduced.The stepped spillway flow pattern,water level,velocity,pressure and energy dissipation of hydraulic characteristics are analyzed through adjusting the layout,the step series and rhe step size of stepped spillway.In this research.It can be showed that the flow pattern of the stepped spillway is divided into transitional flow regime,the flow pattern and the flow pattern of taxi drop.In the setting of transition section,after throughing a transition section,the water flow is influenced by the weightlessness,the water line will drop sharply in the initial stage then recovering gradually.Because of the reaction force of the bottom plate of stilling pool,the water surface line increases suddenly,and the water surface becomes stable after the water reaches steady state.In the pattern of droping flow,an angle of 45 degrees is formed between the flow velocity and the direction of the step level in the internal concave.In the pattern of sliding flow,the velocity direction on the water surface is parallel to the outer edge of the step.A vortex triangle is formed in the step internal flow.After increasing the flow rate,the positive pressure value of step level increases.The maximum value of positive pressure is located at 0.8 steps of step and the minimum point of pressure on the vertical face is easy to produce 50%-65%.