ANALYSIS OF FLOW OVER A STEPPED SPILLWAY USING ANSYS FLUENT 16.0

Abstract

In this dissertation, analysis of flow over a stepped spillway is done. The CFD analysis will concentrate on the energy dissipation caused by the stepped spillway and flow transition from the nappe regime to skimming regime with the variation in discharge for a constant step size. The change in the regime will alter the efficiency of energy dissipation done by the stepped spillway. After studying the flow regimes for different flow discharges and for a constant slope, effect of variation of number of step size (height and length) on the energy dissipation is analyzed. Broadly the project is divided into 3 segments 1) For a fixed step size and a constant slope, variation of flow profile by varying discharge per unit width is studied. This study will tell change in mechanism of energy dissipation 2) For a constant discharge per unit width and a constant slope, variation of the number of steps i.e. changing the height of each steps and varying the number of steps keeping the total height of spillway being the same is analyzed. 3) Comparison of efficiency of stepped and non-stepped spillway The project entails study of the relationship between the critical depth of flow and energy dissipation. The importance of this work is associated with the stability of downstream bed channel. The aim is to reduce the total energy of water overflowing through spillway to a considerable extent such that there is no scouring due to the energy of flowing water on the downstream river bed.