Effect of traveling waves on a long slender cylinder in vortex-induced vibration with two degrees of freedom

This paper introduces a three-dimensional wake-oscillator model to analyze and predict the response characteristics of vortex-induced vibration (VIV) of a long slender cylinder at a low mass ratio. The in-line coupling effects on the variable aspect ratio of the cylinder under different applied current profiles are considered. The nonlinear dynamic model is numerically solved with the time-domain finite-difference method. The oscillation frequency of the cylinder in the in-line direction is twice comparing to the cross-flow direction, showing that the wave travels mostly in the in-line direction. As the flow velocity gradient increases, the oscillation frequency of the cylinder also increases. The energy transfer characteristics of the traveling wave along the cylinder is further analyzed and the varying trajectory patterns observed. (C) 2019 Elsevier Ltd. All rights reserved.