This study describes the development and the analysis of a Computational Fluid Dynamics (CFD) methodology for the simulation of a flow around a circular cylinder. Therefore, the basic hydro mechanical principles occurring during the process have been summed up. In addition, an introduction into CFD and its numerical treatment are given. With this infor- mation, the process of developing a two dimensional and three dimensional simulation with the open source program OpenFOAM is described. The simulation is solved by two solvers: one solver for 2D and one for the 3D simulation. At first the 3D simulation is implemented, with a two-phase incompressible fluid solver, in- terFOAM. For the two dimensional case a shallow water equation solver, shallowFOAM, is implemented. Particular emphasis is placed into the evaluation of the performance of both solvers. Therefore the results are compared to known hydro mechanical principles and to a selected benchmark case. In the evaluation process, the refinement of grid cells is being taken into account and is compared to the necessary computational time. Not only it focuses on the consequences because of the refining of the calculation grid, but also on the consequences caused by the shape of the cylinder. The results of this thesis will provide a framework for an evaluation on the differences and advantages of each solver and the significance of the relation between computational time and mesh refinement. The assessment of the accuracy of the results is conducted in two ways. First by analyzing the vortex shedding and formation of Karmanns vortex street, in which the velocity profile for different flow conditions is being examined. As the vortex shedding is clearer for higher Reynolds number the focus lies on turbulent conditions and the simulations are set up for high Reynolds numbers. In addition, the results are directly compared by the drag coefficient, a normalized drag force appearing on the cylinder. For this coefficient a special drop appears around a Reynolds number of 105 and 2 × 106 . The deviation of the results from other experiments is supposed to be the strongest in this area and also fits the claims for the first comparison. This thesis will give an insight into the importance of mesh refinement and its difficulties. Information over the two different solvers and their possibilities and limitations will be clarified.     «

This study describes the development and the analysis of a Computational Fluid Dynamics (CFD) methodology for the simulation of a flow around a circular cylinder. Therefore, the basic hydro mechanical principles occurring during the process have been summed up. In addition, an introduction into CFD and its numerical treatment are given. With this infor- mation, the process of developing a two dimensional and three dimensional simulation with the open source program OpenFOAM is described. The sim...     »