Physical modeling of flow over an Ogee spillway and investigation of scale effects by using Froude similarity

Abstract

Ogee spillways are used to control the discharges and water levels in reservoir. In some cases, steps and baffle blocks are placed at the stilling basin to change flow regime supercritical to subcritical and improve energy dissipation. Physical models are built in the laboratories to represent its real-world prototype; however some scale effects may arise between models. Two open channel setups, called as model and prototype, are used in this study. The experiments of the study are performed on these channels using identical Froude Numbers and geometric scaling ratio of 4:1. The flow depths at four different points are measured from model and prototype for 28 total head. The results showed that there is 92% consistency between model and prototype, whereas this consistency was not observed at turbulence existing regions due to scale effects.