The Evolutionary Geometric Physics of Vortex-Induced Vibrations

Induced vibrations are multi-dimensional oscillations in a marine riser, suspended wire or other slender structures, whereby the maximum amplitude of deflection is generally perpendicular to the sustained action. In previous OMAE papers, we have shown how sustained actions evolve physical changes in slender structures. Using nonlinear physics-based simulations, we showed how these structural changes fundamentally determine the nature of the vibrations that any sustained action (including flowing fluid around the structure) can induce. In this paper, we step back to focus on a classical laboratory experiment, whereby the structure has been constrained to function as a simple mass-on-spring oscillator. In this unchanging structure, we show how the geometric physics of the fluid drag load induce Vortex-Induced Vibrations (VIV). We show how these vibrations naturally grow in time to maximum amplitude.