Author(s): Yongjun Kwon; Hyung-Suk Kim

Linked Author(s): YongJun Kwon, Hyung Suk Kim

Keywords: Numerical model; Overtopping; Bridge; Turbulent flow

Abstract: A 3D numerical model based on the RANS equations coupling with the density function method was developed to examine the turbulent flow with overtopping around a bridge under extreme hydrologic conditions. Numerical simulations revealed that, under overtopping conditions, the upstream velocity decreased due to the backwater effect, while the maximum flow velocity induced by overtopping reached approximately Uover,max/U =2.0. As the upstream discharge increases, the water -level difference between the upstream and downstream sections becomes more pronounced, generating strong shear layers and extensive recirculation zones downstream of the bridge, along with notable free-surface oscillations. This study provides three-dimensional insights into bridge hydraulics under extreme flow conditions and delivers fundamental hydraulic data that can support future bridge design, evaluation, and maintenance for flood -safety enhancement.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.203

Year: 2026