Forced Vibration Tests for In-Line VIV to Assess Partially Strake-Covered Pipeline Spans

• Published in: Volume 2: CFD and FSI
• Main Authors: Wu, Jie, Yin, Decao, Passano, Elisabeth, Lie, Halvor, Peek, Ralf, Sequeiros, Octavio E., Ang, Sze, Bernardo, Chiara, Atienza, Meliza
• Format: Book Part
• Language: English
• Published: ASME Press 2019
• Subjects: VIV; pure in-line response; partial strake coverage; free-spanning pipeline; VIVANA; SIVANA; Arctic
• Online Access: http://hdl.handle.net/11250/2640095; https://doi.org/10.1115/OMAE2019-95970

A series of experiments is performed in which a strake-covered rigid cylinder undergoes harmonic purely in-line motion while subject to a uniform “flow” created by towing the test rig along SINTEF Ocean’s towing tank. These tests are performed for a range of frequencies and amplitudes of the harmonic motion, to generate added-mass and excitation functions are derived from the in-phase and 90° out-of-phase components of the hydrodynamic force on the pipe, respectively. Using these excitation- and added-mass functions in VIVANA together with those from experiments on bare pipe by Aronsen (2007), the in-line VIV response of partially strake-covered pipeline spans is calculated. It is found that as little as 10% strake coverage at the optimal location effectively suppresses pure in-line VIV. Further advantages of strakes rather than intermediate supports to suppress in-line VIV include: strakes are not affected by the scour which can lower an intermediate support (in addition to creating the span in the first place). Further they do not prevent self-lowering of the pipeline or act as a point of concentration of VIV damage as the spans to each side of the intermediate support grow again. acceptedVersion