An evaluation of computational fluid dynamics for spillway modeling

Abstract

As a part of the design process for hydro-electric generating stations, hydraulic engineers typically conduct some form of model testing. The desired outcome from the testing can vary considerably depending on the specific situation, but often characteristics such as velocity patterns, discharge rating curves, water surface profiles, and pressures at various locations are measured. Due to recent advances in computational power and numerical techniques, it is now possible to obtain much of this information through numerical modeling.

Computational fluid dynamics (CFD) is a type of numerical modeling that is used to solve problems involving fluid flow. Since CFD can provide a faster and more economical solution than physical modeling, hydraulic engineers are interested in verifying the capability of CFD software. Although some literature shows successful comparisons between CFD and physical modeling, a more comprehensive study would provide the required confidence to use numerical modeling for design purposes. This study has examined the ability of the commercial CFD software Flow-3D to model a variety of spillway configurations by making data comparisons to both new and old physical model experimental data. In general, the two types of modeling have been in agreement with the provision that discharge comparisons appear to be dependent on a spillway’s height to design head ratio (P/Hd). Simulation times and required mesh resolution were also examined as part of this study.