Effects of Floating Debris on Flow Characteristics around Slotted Bridge Piers: A Numerical Simulation

Abstract

Bridge pier scouring is a significant concern in hydraulic engineering, requiring thorough investigation under various conditions to estimate maximum scour depth and mitigate the risk of bridge failure. This study aims to conduct a numerical simulation of flow around a bridge pier with slots in the presence of floating debris, with the objective of analyzing variations in parameters such as velocity, shear stress, turbulent intensity, and turbulent kinetic energy. The FLOW−3D software package (Version 11), along with the k−ε (RNG) turbulence model, was employed for the simulation. The results indicate that the presence of a slot in the bridge pier provided a smooth pathway for the flow, resulting in a reduction in the pressure gradient and alleviating the negative impacts on the flow. This, in turn, led to a decrease in the velocity of the flow. Additionally, turbulence intensity around the pier ranges between 0 and 49, while turbulent kinetic energy varies from 0 to 0.005. The findings reveal that models without slots exhibit higher turbulence and vorticity levels, as well as greater flow separation, compared to models with slots. This disparity can be attributed to the slot’s ability to neutralize detrimental lateral and downward flows. Furthermore, the results demonstrate a gradual decrease in shear stress as the flow approaches slotted bridge piers, accompanied by a reduction in vortex intensity. These findings suggest that the accumulation of floating debris can counteract the influence of slots in reducing scour around bridge piers, necessitating thorough consideration during the design phase.