Numerical Modelling of Flow Behaviour Over a Circular Crested Trapezoidal Weir

Abstract

Circular crested weirs have been used for a long time due to their simplicity in design, low cost and accurate measurement. In this research work, a Computational Flow Dynamics (CFD) model has been applied to explore various flow features over a circular crested trapezoidal weir. The volume of fluid (VOF) technique was used in this work. Two weir conditions with and without roughness elements and three discharges values for each weir case were used. The flow characteristics investigated include coefficient of discharge, water surface profiles and velocity profiles. The roughness element remained submerged in all the simulation cases. The k-ɛ turbulence model was used for the CFD simulation. After validation, the flow characteristics were investigated for different flow situations. A comparison was drawn between various flow characteristics for channels with and without roughness elements and different discharge values.