Study On Numerical Simulation Of Flow Field Around A Rectangular Cylinder

The aerodynamic behavior of rectangular cylinder has long attracted the attention of the engineering community for its potential wind engineering application in long-span bridges and high-rise buildings. On the other hand, turbulent, separated and reattached flow around a sharp-edged cylinder at high Reynolds number also makes it an ideal subject to the scientific community for theoretical analysis, wind tunnel experiment and numerical study. The aim of this study is provide a contribution to the understanding of various flow phenomena and its effects on overall aerodynamic behavior, in which the research is carried out as follows:1.The governing equations of incompressible fluid dynamics and the foundation of finite volume method are shortly described first followed by a brief introduction to the discretization of governing equations, i.e. the computation of diffusion term,convection term, transient term and gradient term. A variety of turbulence models and the corresponding strength and weakness are discussed in details according to its catalog where the main emphasis is put on the large eddy simulation due to its arising popularity in literature.2.The high Reynolds number turbulent flow around a fixed sharp-edged rectangular cylinder with three different chord-to-depth ration equal to 1, 2 and 5 respectively are numerically studied using the technique of large eddy simulation. The aerodynamic parameters and pressure field acting on the rigid cylinder along with other useful flow field information are recorded and compared with other results proposed in literature.3.Some flow features of the shear, separated and reattached flow around the cylinder with a chord-to-depth ration equals to 5 and its contribution to the overall aerodynamic behavior are analyzed. The 3D flowfeatures around the nominally 2D cylinders are also investigated by means of both proper orthogonal decomposition and coherence function of the side-surface fluctuating pressure field.The computational approach post processing facilities are employed to shed some light on the relationships between vortex shedding and convection mechanisms, the instantaneous pressure field and aerodynamic forces.