Assessment of CFD turbulence models for free surface flow simulation and 1-D modelling for water level calculations over a broad-crested weir floodway

Abstract

Floodways, where a road embankment is permitted to be overtopped by /f_lood water, are usually designed as broad-crested weirs. Determination of the water level above the /f_loodway is crucial and related to road safety. Hydraulic performance of /f_loodways can be assessed numerically using 1-D modelling or 3-D simulation using computational /f_luid dynamics (CFD) packages. Turbulence modelling is one of the key elements in CFD simulations. A wide variety of turbulence models are utilized in CFD packages; in order to identify the most relevant turbulence model for the case in question, 96 3-D CFD simulations were conducted using Flow-3D package, for 24 broad-crested weir con/f_igurations selected based on experimental data from a previous study. Four turbulence models (one-equation, k-ε , RNG k-ε , and k-ω) ere examined for each con/f_iguration. /T_he volume of /f_luid (VOF) algorithm was adopted for free water surface determination. In addition, 24 1-D simulations using HEC-RAS-1-D were conducted for comparison with CFD results and experimental data.

Categories