Abstract
The phenomena of Vortex Induced Vibration (VIV) could be observed frequently in the daily life. In the downstream region of a structure immersed in the flow field, it usually performs the pattern of the vortex street with the highly turbulent viscosity, which is caused by the vortex shedding from separating shear layers of the structure. In Computational Fluid Dynamic, there have been many models, such as mixed length model and k-ε model, used for turbulent flow simulation at highly Reynolds numbers. However, the mathematic theory of these models based on the Reynolds-Averaged Navier-Stokes equation (RANS), often represent extremely complicated form and need to be corrected with the experiment database. Also, they are not appropriate to be used to regenerate the unsteady flow field. Currently, Large Eddy Simulation (LES) is a proper choice, due to the capacity of simulation with the unsteady and complicated properties of turbulent. The primary purpose of this thesis is to investigate the core part of LES, Sub-Grid Scale models (SGS models), and to build two dimension simulation of circular cylinder turbulent flow. On the one hand, this study could be extending the ability of simulation of unsteady, complicated geometric structure flow. On the other hand, the uneasily estimated or unestimated parameters, such as pressure field, drag and lift coefficient, vortex frequency, turbulent statistic properties, etc., are quantified to verify the overall performance of the LES with turbulent flow simulation, and study the physics of turbulent flow in depth. The study shows that the effect with several types of SGS models is insignificant for flow statistics, except for the time-averaged resolved cross-flow velocity distribution. In addition, two dimension simulation is unsatisfying to represent certain flow characteristic properties, even result in incorrect outcome as Reynolds number is higher than 1500. Three dimension numerical simulations should be top priority in future work.Keyword: CFD, LES, SGS models