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 cylind er was conducted in a unique experimental facility especially designed for low mass and low damping. In this low mass-damping regime, two se parate regions of the high amplitude response curve were identified, w hich we label ''upper'' and ''lower'' branches of response. A systemat ic study including twelve responses was performed to determine the eff ect of separately varying the nondimensional mass and varying the nond imensional damping. It seems apparent over the range of our present in vestigation that the mass-damping (the product of mass and damping) co llapses well the amplitude of response, indicating two distinct amplit ude curves, rather than the single, unique relationship previously sup posed.