The Numerical Simulation And Study Of Flow Around Cylinders

Flow around bluff bodies is very broad in the actual engineering, such as inter-wing pillars of aircraft, submarine snorkel, high-voltage transmission lines and the flow on the bridge, pillars of the marine drilling platforms, submarine transport pipe lines, pile piers, etc, there are important engineering background. And the flow around a cylinder is the most classical flow problems in the flow around bluff bodies. Flow around a cylinder is unsteady separated flow problems, which is also very extensive in industrial engineering. Flow around a cylinder is also a classical fluid problem, when fluid flow around a cylinder, the over-current section is contracted, the velocity increases along the run, the pressure decreases along the way, due to the presence of viscous forces, the fluid would form a boundary layer separation around the cylinder and form the flow around a cylinder, and because the existence of the cylinder, the fluid will generate the backwater phenomenon in the welcoming water face of the cylinder, but also increases the cylinder force, which makes flow around a cylinder becoming very complicated.This paper applied the CFD method to simulate the flow around a cylinder which is the most classical flow problems in the flow around bluff bodies. Many experimental studies of tradition because of its own limitations (such as model size, experimental period, capital investment, etc.) are difficult to bring more accurate results, but the advantages of the numerical simulation are not impacted human factors and limited the physical model and experimental model, it has better adaptability, strong flexibility, and is fairly wide, that can simulate more fluid flow problems, so it can more accurately meet the engineering requirements.In this paper, using computational fluid dynamics software FLUENT to conduct two-dimensional numerical simulation for the flow around a fixed single or double cylinders under the N-S equations of the viscous incompressible fluid flow, which obtains flow pattern of flow around the single-cylinder, pressure, velocity, vorticity contour and velocity vector and so on. Analyzing movement and loss of the cylindrical vortex, changes of the lift and drag coefficient and the cylinder boundary layer separation points through the results of the numerical simulation., and preliminary analyzing the flow characteristics of the flow around serial and parallel double cylinders, and with the existing experimental results and theoretical results are compared, the analysis gives more accurate results, and verifies the reliability of the numerical solution of the problem.Results of this study in this paper help to understand the formation mechanism of movement and shedding of the flow around a bluff body vortex and the resulting changes of the flow lift and drag coefficient, which provides the study guide and application value to the other flow problems in the engineering.