Three-dimensionality of mode transition in vortex-induced vibrations of a circular cylinder

Abstract End lift forces and hot-wire anemometry in the wake of a flexibly-mounted rigid cylinder, undergoing vortex-induced vibrations within a uniform flow, show that the spanwise correlation undergoes a sharp reduction near conditions of maximum amplitude. Peak lift force and motion amplitudes occur on the low-velocity side of this low-correlation region; the region is bounded above by the advent of frequency lock-in. Certain aspects of this correlation loss are interpreted in the context of other free- and forced-vibration tests, and highlight the sensitivity of three-dimensional effects to the physical parameters.