Investigation of relative effects of mass and damping in vortex-induced vibration of a circular cylinder

An experimental study of vortex-induced vibration of a circular cylinder was conducted in a unique experimental facility especially designed for low mass and low damping. In this low mass-damping regime, two separate regions of the high amplitude response curve were identified, which we label "upper" and "lower" branches of response. A systematic study including twelve responses was performed to determine the effect of separately varying the nondimensional mass and varying the nondimensional damping. It seems apparent over the range of our present investigation that the mass-damping (the product of mass and damping) collapses well the amplitude of response, indicating two distinct amplitude curves, rather than the single, unique relationship previously supposed.