LAUSR

Abstract The objective of this article is to introduce a modified wake-oscillator model to systematically analyze and predict response characteristics and hydrodynamic coefficients of vortex-induced vibration (VIV) of an elastically mounted cylinder with the low mass ratio in two-degree-of-freedom (2-DOF). According to two-dimensional potential flow theory and discrete vortices, the in-line and cross-flow fluctuating vortex forces are simplified and quantified. The model is based on a nonlinear van der Pol oscillator coupled with the cylinder motion and solved by numerical method. The dynamical behavior of the coupled model is investigated and the empirical parameters in the fluid oscillator are calibrated against experimental results. Direct comparison of numerical and experimental results shows that the model qualitatively and quantitatively captures the main dynamic features in 2-DOF VIV, such as oscillation amplitudes, lock-in ranges, hydrodynamic coefficients, phase angles, and X-Y trajectories.