Vortex-Induced Vibrations of Risers Due to FPDSO Heave Motions

Based on the concept design of FPDSO, mechanical model of risers with variable tension is presented, and fluid forces and submerged weight are considered. The dynamic analysis is done to research the influence of FPDSO heave motion to vortex-induced vibrations. The numerical results reflect that risers have large response under the combined action of “lock in” and parametric resonance, and amplitude of heave motion has little effect on the vibrations; tension due to heave motion can significantly increase the forces of the risers.