Research on water flow characteristics and stress around bridges during floods

Abstract

ABSTRACT Due to the frequent threat of floods to structures and engineering constructions near rivers, this study examines the impact characteristics of river hydrodynamics on structures under excessive flow during floods, using Jiefang Bridge as an example. We employ the fluid volume two-phase flow model (volume of fluid) in computational fluid dynamics, combined with advanced geometric reconstruction techniques such as the isoAdvector method, to simulate the dynamic changes of the gas–liquid interface in the river. On the premise of ensuring grid independence, high-precision structural grids were used to finely divide the study area and numerical simulations were conducted. The research results indicate that when a flood contacts a bridge, the force on the bridge rapidly increases and fluctuates, reaching a significant peak of over 6,000,000 N. Bridge piers have a significant hindering effect on floods and their impact gradually expands over time. Vorticity and turbulence energy analysis indicate the presence of strong flow disturbances around the bridge pier. In addition, the characteristics of the contact surface between water flow and bridges also significantly affect the stress and flow characteristics of bridges. Especially at a 45° angle of attack, the force on the bridge decreases, but the wake velocity increases.