Large-eddy Simulation of Turbulent Free Surface Flows Past a Surface-piercing Circular Cylinder

A three-dimensional numerical study has been undertaken to investigate the interactions of free-surface flows and a surface-piercing circular cylinder. 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 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. The LES code is validated with the help of various benchmark problems for dam-break flows over structures, and it is demonstrated that both the free-surface and velocity field are captured successfully by the code. Numerical results are presented and compared with the available experimental measurements. Detailed free surface profile, velocity fields and vortical structures in the vicinity of the cylinder are shown and discussed.