A Computational Fluid Dynamics Based 2nd Order Upwind Scheme for Free Surface Flows

Detailed understanding of free surface flows is of interest in fields as diverse as environmental engineering (sewage overflow structures) to chemical engineering reactive flows. To gain the required level of detail for modelling such flows it is necessary to employ CFD, which, in turn, require suitable turbulence models. In order to develop suitable turbulence models, even more detail is required to extend the fundamental understanding of turbulence before developing approximate methods. A zero equation model for Large Eddy Simulations based on a second order upwind discretisation scheme has therefore been developed for this purpose. This method differs significantly from other zero equation LES type as it correctly captures the turbulent energy cascade. A validation study was applied to the simulation of a free surface piercing circular cylinder moving in an otherwise stationary fluid. Frequency analysis, together with point and integral data, was used to compare with published data of similar cases and found to be within good agreement. Qualitative analysis of the flow field shows patterns consistent with flow around pier-type structures.