Inline-Crossflow Coupled Vortex Induced Vibrations of Long Flexible Cylinders

• Published in: Volume 5: Ocean Engineering; CFD and VIV
• Main Authors: Modarres-Sadeghi, Yahya, Dahl, Jason, Zheng, Haining, Triantafyllou, Michael S
• Other Authors: Massachusetts Institute of Technology. Department of Mechanical Engineering
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Society of Mechanical Engineers 2019
• Subjects: Arctic
• Online Access: http://hdl.handle.net/1721.1/120740

The inline motion of long flexible cylinders caused by Vortex Induced Vibrations (VIV) has been long neglected due to its small amplitude compared to the cross-flow response amplitude. However, the inline motion has a major impact on fatigue life due to its higher frequency (second harmonic) and more importantly, because it triggers a third harmonic stress component in the crossflow direction along with a broad-band frequency stress component. We introduce an inline response prediction module to VIVA, a VIV response prediction program widely used in the offshore industry, to be able to consequently predict the higher harmonic and chaotic VIV response characteristics of flexible cylinders. Extensive forced inline and combined inline-crossflow experiments were employed to provide hydrodynamic coefficient databases for input to VIVA, in addition to existing crossflow hydrodynamic coefficients. The Norwegian Deepwater Programme (NDP) experimental data were used to validate this prediction methodology. BP-MIT Major Projects Program