Numerical assessment of the inception point in different stepped spillway configurations

Abstract

Many studies on several aspects of the flow characteristics over a stepped spillway such as air entrainment, velocity profiles, and energy dissipation were mostly based on physical models and more recently with computers flagrant revolution on CFD. This latter presents clear advantage as reducing laboratory testing which leads to time optimization, and cost reducing. However, CFD is not still accepted without careful validation and verification. The aim of this article is to show the reliability of numerical modeling through results of k-ɛ RNG turbulence model and using volume of fluid (VOF) method to achieve inception point location. Different stepped spillway configurations were simulated with two different slopes (14° and 26.6°) and different step heights for a large range of flows. The results on velocities profiles obtained by the numerical simulations were in accordance with experimental data, which allowed the analysis of inception point location that fits experimental results as well as the empirical formulas presented by different researchers. A methodology to achieve inception point, based on CFD, is presented, verified, and validated, contributing to the acceptation of CFD.