In-Line Motion of Subsea Pipeline Span Models Experiencing Vortex-Shedding

Subsea pipeline spans, when experiencing bottom ocean currents, are prone to vortex-induced vibration (VIV). Experiments and computational fluid dynamics (CFD) are conducted to evaluate the effects of the pipe stiffness on its first mode in-line VIV motion, primarily in the reduced velocity range from approximately 1.0 to 4.0. Experimental results also indicated that there was obliqueness in motion trajectories, which could have impacts on VIV design of the free spans. The main findings of this investigation are presented in this paper.