Numerical investigation of the flow behavior around a single cylinder using Large Eddy Simulation model

In Large Eddy Simulation (LES), the cost of resolving the boundary layer on a solid wall boundary is high. One way to overcome this difficulty is to employ a wall model that can provide the approximate wall boundary conditions into the LES solution. In addition to the wall model, selecting a proper sub-grid model in the LES solution can affect computational time. In this study, the applicability of the Smagorinsky sub-grid model and of a simple wall model was investigated by simulating the turbulent flow past the square and circular cylinders, which are relevant case-studies for marine structures supported by piles. The simple wall model is based on the turbulent boundary layer equations. A solution procedure was developed to solve the set of the flow equations and then calculations were performed by considering different values of the Smagorinsky coefficient and different definitions to compute the spatial filter width scale. The corresponding numerical results are in good agreement with those extracted from available experimental and numerical data at different cylinder Reynolds numbers. The solution procedure used in this study has low computational cost such that all calculations could be performed on a single computer in a short period of time.