Coupled-oscillator models for vortex-induced oscillation of a circular cylinder

The vortex-induced oscillation of a circular cylinder is modelled by a non-linear system with two degrees of freedom. The periodic lift acting on the cylinder due to the vortex-street wake is represented by a self-excited oscillator, which is coupled to the cylinder motion. Approximate solutions and stability criteria are presented which are valid over restricted intervals. Changes to the form of the coupled-oscillator model and its approximate solution are examined in order to improve the comparison between predicted model and experimental results. The changes are motivated by the study of experimental evidence, and by comparison with the known properties of similar systems of non-linear equations. Significant improvement in the coupled-oscillator model performance is obtained through the inclusion of an effective structural damping term which is dependent on wind speed and cylinder displacement.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat