Numerical simulation of flow around a cylinder of two degrees of freedom motion using the discrete vortex method

The problem of the two-dimensional flow around a cylinder with elastic support is investigated using Discrete Vortex Method(DVM).By conducting the system simulation of the one-dimensional transverse motion,the two-dimensional transverse and flow direction motion,the wake shapes,lift coefficients and response amplitudes of different mass ratios and reduced velocities are obtained.Comparisons are made between the transverse amplitudes for single degree of freedom and two degrees of freedom systems.The characteristics of the motion responses of the cylinder in different mass ratios and degree of freedoms are summarized.The lock-in phenomenon of Vortex-Induced Vibration can be observed successfully in the simulation and the simulated results have a very good agreement with the experimental results,which proves that the Discrete Vortex Method(DVM) is simple and robust for the investigation of the Vortex-Induced Vibration,especially having advantages for the simulation with high Reynolds number.The simulation results show that Vortex-Induced Vibration may be enhanced by the flow direction motion.The whole calculation program for the problem was written in FORTRAN language.