A Model Scale Experimental Investigation on Vortex-Self Induced Vibrations (VSIV) of Catenary Risers

Vortex Self-Induced Vibrations (VSIV) of a reduced scale model of a catenary riser are experimentally investigated. The riser model dynamics was assessed with a submerged optical motion capture system and significant VSIV were revealed as result of oscillatory vertical motion imposed to the top. Such a behavior recovers similar ones reported in the technical literature by other authors and resembles previous fundamental studies, by Sumer and Fredsoe, with rigid cylinders forced to oscillate in a plane and elastically mounted in the transversal direction. The present experiments are preliminary and pertain to a much more comprehensive experimental set, within a research project aimed at studying the nonlinear dynamic behavior of risers, through experimentally validated analytical and numerical, nonlinear reduced-order models.