Numerical modelling of Flow characteristics over sharp crested triangular and W-shaped weirs for establishing downstream scour behavior

Abstract

Weirs are flow control devices that are often used in waterways. As the weirs by nature change the flow patterns in the water ways, significant changes in the flow structure in the vicinity of the weir structure can be easily seen. These significant changes in the flow patterns create significant changes in the surrounding flow geometries. Scour in the downstream of the weir is fairly well-known side effect in the channels. The objective of this study is to evaluate the flow characteristics of a triangular sharp crested weir and its comparison with W-shaped sharp crested weir using CFD (Computational Fluid Dynamics) with Ansys Fluent as the main tool. Important flow characteristics, before and after two weir shapes have been evaluated and their potential to cause scour in the downstream evaluated with a view establish relationship between weir shape and the likely scour area has been investigated. It has been found that weir shape has significant influence on scour behaviour and this study may be used a reference for future evaluation of scour potential of weirs of different shapes.