| Free overfall is a basic hydraulic phenomenon in nature and engineering. It plays the role of energy dissipation, improving water and conveying water etc. The flow characteristics of the free overfall are general of three dimensional and turbulent, including the complicated free surface.First, A comprehensive review and expectation about research status are given in this paper.Second , The Volume of Fluid(VOF) method is introduced to the κ-ε turbulence model and combined the geometry reconstruction scheme to solve the free surface. The numerical model is established by solving the domain using structural girds.Based on the built model, the hydraulic characteristics and the relations including flow pattern ,velocity field ,free surface , energy loss etc. are discussed quality and qualitatively by applying different flow rates and drop heights.The numerical simulation results are compared with the results of the other researchers, which are agreed well with each other. The methods about how to develop model and refine the local grids are discussed. This will be helpful for the numerical precision and efficiency.
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