Author(s): Zhihua Xie; Santiago Martelo; Thorsten Stoesser; Junqiang Xia; Pengzhi Lin
Keywords: Large-eddy simulation; Volume-of-fluid method; Fluid-structure interaction; Two-phase flow; Rough bed
Abstract: The interfacial flows are present in a wide range of flows that are of interest within engineering applications, from the ubiquitous open-channel flow to coastal and marine hydrodynamics. Although many investigations have been undertaken to study such turbulent flow fields, the current understanding of the roughness effect on the turbulent properties of interfacial flows is still limited. A three-dimensional numerical study has been undertaken to investigate turbulent free-surface flows over rough beds. A two-phase flow model has been developed and the large-eddy simulation (LES) approach has been adopted in the study, for which the filtered Navier–Stokes equations are solved and the dynamic Smagorinsky sub-grid model is employed to compute the unresolved scales of turbulence. The governing equations have been discretised using the finite volume method, with the air–water interface being captured using a volume of fluid method and the cut-cell method being implemented to deal with complex geometry in the Cartesian grid. Several numerical examples of turbulent interfacial flow problems are presented to demonstrate the ability of the numerical framework. Detailed mean flow field and turbulence structures will be shown and their interaction with the interface will be discussed.