3-D Numerical Simulation Of Scouring Process In Downstream Of Sluice Gate

Low-head hydropower plants with a low head, big flow and small Froude number.Erosion damage occurred very common in the apron and pavement downstream of sluice gates, especially in cross-strait slope the erosion is more serious. Therefore correct prediction about the internal flow field information, the process of scouring, the shape and depth of approximate equilibrium of the scour at downstream of discharge structures is of great significance for the security of discharge structures.With the model of Juting hydropower station for the study, set by ANSYS FLUENT software, the three dimensional numerical simulation of flow field and the discharge process water erosion process were simulated. The results obtained can be summarized as follows:(1) Three-dimensional mathematical model was established to simulate the flow field of the model of Juting hydropower station, with k-epsilon turbulence model used to close N-S equations, finite volume method being used to discrete grid, VOF being used to track location of water surface; A reasonable flow field numerical simulation such as the discharge, water surface profile and velocity distribution can be obtained and composition the flow field information of hydraulic model and the results of computing verified the accuracy of the mathematical model;(2) The wall shear stress was taken as the starter criterion obtained using ANSYS FLUENT UDF program wrote with C program language to control the movement of the grid of the bottom boundary and the dynamic mesh model to achieve the reconstruction of the inter grid at erosion area. The process of local souring was obtained by numerical simulation.The numerical simulation results of the maximum scour depth and shape of the river bed downstream of coincided well with physical model test values;(3) Smoothing method and remeshing method used to update the grid, make deformation focus on the bottom boundary in scouring process, the grid near the bottom boundary on moving is finer; it improves the adaptability of grid and accuracy of result;(4) The wall shear stress and turbulence kinetic energy on the bed show gradually decreasing in souring process; the wall shear stress and turbulence kinetic energy decrease along the way upstream the deepest point; the variation of wall shear stress and turbulence kinetic energy is small along the way downstream the deepest point in equilibrium scour pit.