| The Sand Funnel is one kind of new sediment ejection technology and is widely applied for its merits such as high interception efficiency and low water consumption rate. But the flow field characteristics of the Sand Funnel and its mechanism of sediment transport are not yet fully understood heretofore. In recent years, along with the numerical simulation technology development, it is one new research way to try to numerically simulate the flow in the Sand Funnel accurately. Since there is a surface vortex and two exits in the Sand Funnel, the 3-D numerical simulation of turbulent flow in the Sand Funnel has a very great difficulty. This paper has effectively reduced its difficulty through a series of simplifications and disposal, finally establish two physical model of the Sand Funnel respectively with and without adjusting pier.This paper combines the RNG k ?εturbulence model and Volume of Fluid method (VOF) to establish the two phase mathematical model of the Sand Funnel. The commercial computational fluid dynamics (CFD) package FLUENT is used to solve the equations of the model. Distribution of velocity, pressure, turbulence kinetic and vorticity are obtained by simulation. The numerical simulation results are compared with test results, and they are agreed well with each other.Analyzing the result of numerical simulation of 3-D turbulent flow in the Sand Funnel, the author obtains the flowing main conclusions and findings:(1) The current near the base slope has greater radial velocity, proving that there is secondary flow in the Sand Funnel.(2) The upward axial velocity and outward radial velocity of the flow in the Sand Funnel are at suitable region, thus ensuring its low water consumption rate.(3) This paper proposes a secondary flow principle for sediment transportation in the Sand Funnel for the first time.
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