Numerical simulation of flow over rectangular broad-crested weirs including various upstream and downstream sloping faces

Year 2025, Volume: 9 Issue: 2, 38 - 48

Farzin Salmasi , Akram Abbaspour

Abstract

A weir is one of the oldest man-made hydraulic structures, which is used to measure and regulate water flow. The flow passing over a weir is turbulent and is accompanied by mixing of water and air. In this study, the flow passing over two types of broad-crested weirs, i.e., ARB and BRA with downstream and upstream sloping faces is simulated in two dimensions. The standard K-ε model is used to predict free flow surface with volume of fluid (VOF) method. The results of the numerical model for the hydraulic parameters like discharge coefficient, flow velocity and boundary layer development are compared with experimental results and existing relations. The results showed that the standard K-ε turbulence model and the VOF method are suitable for predicting the water surface profile on broad-crested weirs for estimating the discharge coefficient (Cd) and velocity profiles at different distances on the crest. The maximum relative error for the hydraulic head (h1) and Cd is 4.06% and 6.54%, respectively, which is acceptable.

Keywords

Fluid volume fraction , broad-crested weir , discharge coefficient , fluent , K-ε turbulence model

Project Number

123

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