Vortex-induced vibrations and wake induced oscillations using wake oscillator model Comparison on 2D response with experiments

Mooring and flow lines involved in offshore systems for oil production are submitted to various solicitations. Among them the effects of current are dominating. Vortex-Induced Vibrations (VIV) and Wake-Induced Oscillations (WIO) on closely spaced marine risers may lead to fatigue, clashes and structural failures. Extended studies have been conducted to describe and explain them for spring mounted uniform cylinders in translation perpendicularly to their main axis [1]. In the case of a pivoted cylinder with uniform diameter [2] a similar response is observed with some variations on the reduced velocity interval and maximum response. However, complementary studies are necessary to improve our understanding of the hydrodynamic loads acting on risers placed in the wake of an upstream one.