A numerical investigation of flow over a side weir based on the experimental data

Side weirs are one of the most important and sensitive parts of flood water spreading systems. Their inappropriate or incorrect function can potentially have an adverse effect on the entire system, making it difficult for flood water spreading systems to perform correctly. Hence, it is necessary to study the hydraulic behaviour of the side weirs. One of the applications of side weirs is predicting the accurate flow measurement in irrigation and floodwater spreading systems. In this study, flow over a broad-crested side weir is numerically investigated based on experimental data under sub-critical condition. The numerical model considers flow over a side weir using Reynolds's Average Navier-Stokes (RANS) equations. The standard k-epsilon turbulence is used to account for turbulence modelling and the volume of fluid scheme was also used in the model to find the free surface of flow. The simulation results are validated by experimental data. They provide detailed analysis of flow patterns, longitudinal pressure distributions over the side weir and also outflow discharge. This study shows that existing numerical models using RANS are applicable in the design of side weirs.