Validation of the Volume of Fluid Method for Free Surface Calculation: The Broad-Crested Weir

Abstract

This paper describes the validation of Computational Fluid Dynamics (CFD) for modelling free surface flows over common hydraulic structures. A series of CFD simulations are compared against an existing set of experimental data for the free surface flow over a broad-crested weir. By fixing the upstream and downstream water depths in the CFD model, it was possible to reproduce the experimental free surface profiles, pressure and velocity profiles and discharges over the weir for a range of discharge rates. The sensitivity of the results to the choice of turbulence model is presented. Gaining confidence in a modeling technique in this way, allows for the future modeling of more complex hydraulic structures and the introduction of the more complex physics required for modeling processes such as scour.