Experimental Investigation on the Vortex-Induced Vibration (VIV) Suppression of the Umbilical Cable Attached with Helical Strakes

Vortex-induced vibration (VIV) is very important to riser as VIV is closely related to fatigue damage. Literature reviews demonstrate that very limited work has been done to address the vortex-induced vibration suppression of the umbilical cable. To bridge the gap, this paper proposes a novel umbilical cable model and investigates the vortex-induced vibration and VIV suppression of the umbilical cable attached with helical strakes. The umbilical model is a composite of an acrylic pipe and a seven-wire strand. The strands are formed in the same machine by seven reels of copper wire with a certain helix angle, 9 degrees. Both the unbonded umbilical cable and the bonded umbilical cable are tested in the experiment. The results indicates that maximum response amplitude of the unbonded umbilic cable is larger than the maximum response amplitude of the bonded umbilical cable. The stick-slip behavior of umbilical cable and its relationship to damping has been revealed. The umbilical cable with helical strakes achieves a significant suppression compared to the umbilical cable without helical strakes.