Numerical Simulation Of Flows At Closure Gap

Qingcaosha reservoir is a strategic project to solve the fresh water lack during the development of society and economic of Shanghai. The hydraulic computation and analysis at the closure of the reservoir dike is important to the construction of the project in the Yangtze estuary. The traditional practical method based on water mass conservation to calculate the hydraulic factors is no longer fit for practice of construction, so the numerical simulation of the complicated flows with the free surface is developed to compute the hydraulic factors at the closure.The flow around closure can be simplified to a vertical 2-dimentional flow over a weir. Using FLUENT, the weir flow was simulated and the typical flow patterns, water levels and the distributions of velocity were validated with the experimental data available. In order to check the possibility of modeling the complicated turbulent flows with the free surface over a weir by the use of the shallow water equations, it was carried out that, under the same profile of weir and boundary conditions, the distributions of maximal velocities along the flow over the weir were obtained using both DELFT-3D and FLUENT respectively and were compared carefully.Given boundary conditions of water level, the vertical 2-dimensional flow around the closure of Qingcaosha reservoir was simulated according to the design profile of the vertical section of the project. The four typical flow patterns were reported. Given boundary conditions of tidal level, the flow around the closure was simulated using FLUENT and DELFT-3D respectively and the maximal velocities and the locations of them were compared.The 3-dimensional flows around the subsidiary and primary closures were simulated at each project node of Qingcaosha reservoir using DELFT-3D. The maximal velocities and their locations were computed and compared, which would be useful for design of the project.