The Three-dimensional Numerical Simulation On Flood Sluce Of Xiaowan River Reservoir Stepped Spillway

Stepped spillway is a facility of energy dissipater with discharge and energy dissipation,the energy dissipation effect is good and the construction cost is low. With the development ofroller compacted concrete technology, stepped spillway has been widely used. Therefore, theresearch on hydraulic characteristics of stepped spillways is of important practicalsignificance. we usually used physical model test and numerical simulation methods to studythe hydraulic characteristics of stepped spillway. In recent years, with the development ofincreasing computer performance and computational fluid dynamics, numerical simulationtechnology has become an important means of research on hydraulic characteristics ofstepped spillway. In this paper, the hydraulic characteristics of stepped spillways werestudied by means of numerical simulation methods, the main research results are as follows:Created three-dimensional models in CAD, divided unstructured grids in the ICEM,used FLUENT software, selected standard k-ε turbulence and VOF method to studyXiaowan River stepped spillway with numerical simulation in unsteady flow. The Numericalsimulation and model test results fit well by comparison.The water flow on stepped spillways of Xiaowan River was skimming flow. Stepsgenerated clockwise swirl, Rate of flow was zero in the vortex center, then increased to thesurrounding. The turbulent energy and dissipation rate of turbulence on steps are quite similar,the step concave corners is considered as the center, they gradually increase to four weeks, theformer reaches the maximum in convex corners of steps, while the latter is on both sides ofstep convex corner. The vertical plane of the step portion has a negative pressure zone, withthe stepped down, the negative pressure region become smaller. The bottom of the stairsappears the maximum positive pressure. Along a vertical plane, pressure gradually reduce tonegative pressure., and then increases. In the horizontal plane of steps, pressure are basicallypositive, but in the horizontal edges may appear less negative pressure. Along a horizontalplane from concave corner, the pressure distribute as follows: first decreases and thenincreases, decreases sharply after reaching the maximum, or even negative. And try toalleviate the negative pressure with the way of aeration in first steps.