Vortex-Induced Vibrations (VIV) are three-dimensional (3D) oscillations of slender structures that are induced by fluid vortices shedding off the moving structure. VIV is intriguing because the largest magnitude of the oscillations is generally perpendicular to the incident fluid flow. Much of the historical research in VIV has focused on the inducing hydraulics of this fluid/structure interaction. We instead focus on the structural mechanics for valuable insights as to why and how VIV physically occurs. We first review the basic mechanics of a suspended pipeline that is horizontally-oriented and then explore the same for a marine riser that is vertically-oriented. In particular, we will investigate the following:
• How gravity and fluid drag curves the slender structures
• How this global curvature locally promotes VIV
• How period doubling is a natural consequence of geometry
• How changes in boundary conditions, shedding periodicity, fluid drag, and fluid velocity affect VIV
