ANALYSIS OF FLOW OVER A STEPPED SPILLWAY USING ANSYS FLUENT

Abstract

In this Dissertation, the flow over a stepped spillway will be analyzed. The CFD analysis will focus on the energy dissipation which is caused by stepped spillway and transition of flow from nappe regime to skimming regime with the change in step size(height and length) for a constant slope and discharge and variation of discharge with constant step size and slope. As the regime condition are changed, there will be the change in the efficiency of energy dissipation by the stepped spillway. After studying the different flow regimes for different step sizes, I will compare the variation of energy dissipation with manual calculations of energy dissipation on stepped spillway. The project is divided into 3 segments: 1. For a constant discharge per unit width and a constant slope, variation of the number of steps i.e. changing the height and length of steps by varying the no. of steps keeping the total height of spillway being same is analyzed. 2. For fixed step size and constant slope, variation of flow profile by varying discharge per unit width is studied. 3. Comparison of above stepped spillway results with the manual approach is done. This work is very important related to the stability of downstream bed channel. The aim of project is to reduce the total energy of water flowing over a spillway to a considerable extent so that scouring will be minimized due to the energy of flowing water on the downstream side of river bed.