Laboratory experiments and numerical model of local scour around submerged sharp crested weirs

Abstract

The use of theoretical models, with multiphase flow (air, water, and sand), is lacking in prior research for the simulation and management of erosion around hydraulic structures. In this research, flume experiments and a Computational Fluid Dynamic (CFD) model were used to study flow properties and scour around four new shapes of submerged weir: inclined sharp crested weirs with 30° and 120° slopes, respectively, and two different vertical arch weirs. The proposed weir shapes were compared against a sharp crested weir to investigate any potential reduction in scouring at different discharges. The results showed that the inclined sharp crested weir with a 120° angle reduced the maximum scour depth by more than three times compared to the sharp crested weir. The results also indicated that there was a statistically significant difference between the CFD simulation and the flume experiments for both the sharp crested weir and the inclined weir with a 120° angle. This research supports the design and use of inclined weirs with 120° angles for the alleviation of scour around hydraulic structures. Keywords: Submerged weir, Multiphase flow, Scour depth, Flume experiments, CFD