Two-dimensional Numerical Simulation Of Flow Around A Cylinder And Vortex-induced Vibration

Flow over a cylinder phenomenon, which assumes cylinder is fixed, is the scope of aerodynamics; cylindrical vortex-induced vibration, which considers cylinder vibration, is areas of aeroelasticity. This paper will use numerical simulation method to analyze the characteristics of the two phenomena in order to provide reference value for engineering research and practiceThe Reynolds number plays a decisive role in flow over circular cylinder which is also affected by many factors, such as blocking ratio, turbulence, and the downstream boundary conditions. Based on flow over circular cylinder, the study firstly establishes two-dimensional flow field model of single circular cylinder and serial dual cylinder, calculates flow for a Re = 200single circular cylinder using the fluid software CFX, and compares the results with the literature results to prove the reliability of this calculating method in this study. Then the present study calculates the flow of single circular cylinder under the condition of the Reynolds number to get the lift and resistance coefficient, and variation laws of Strouhal, and analyzes changes of flow field through the flow chart and flow velocity cloud chart. After that, the study calculates the flow of serial dual cylinder under the condition of different pitch, gets the critical distance of dual cylinder flow by analyzing lift and drag coefficient of flow, and analyze changes of flow field at different pitches through the flow chart and flow velocity cloud chart.Vortex-induced vibration phenomenon often happens in civil engineering structures, particularly in long-span bridges. Vortex induced vibration can easily cause the vibration of the main beams and cables.In terms of the phenomenon of vortex induced vibration, the study adopts the problem of Ansys + CFX numerical stimulation fluid coupling. Two-dimensional cylinder is simplified as mass-spring damper system, and the accuracy of numerical model is verified by modal analysis. Then, the study fixes the structural parameters, and analyzes the different response of cylinder and the flow field between lock range and non-locking range by changing wind speed to capture the lock range parameters.