Reliable Bridge Scour Simulation Using Eulerian Two-Phase Flow Theory

Abstract

A CFD-based simulation methodology for bridge scour using an Eulerian two-phase flow model is proposed in the present study. The basic conservation equations and four unique simulation issues are firstly addressed during the model establishment process. The solutions are given to each of the four simulation challenges, and the discrepancies between the two-phase and single-phase modeling methods are clarified. Secondly, based on the Eulerian two-phase flow theory, a three dimensional (3D) bridge scour model is numerically established by redeveloping a commercial computational fluid dynamics (CFD) program. A comparison between the numerical results and measurements in a classic experiment from the literature validate the proposed simulation methodology that can comprehensively predict the flow field and scour (riverbed) profile. The accuracy advantages over the single-phase flow model are demonstrated from three aspects including the scour-hole profile, flow field, and scour depth. Finally, a parametric analysis using the two-phase flow model-based simulation is carried out to investigate the impacts of environmental and design parameters on the characteristics of scour developments. It can be concluded that the proposed two-phase flow model-based simulation can support more-reliable scouring safety analysis of bridge pier designs compared with the widely used single-phase flow model-based approach.