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Lookup NU author(s): Professor Zhiqiang Hu
This is the authors' accepted manuscript of an article that has been published in its final definitive form by A I P Publishing LLC, 2016.
For re-use rights please refer to the publisher's terms and conditions.
This article presents the research findings of an extensive model test investigation of the dynamic response to vortex-induced motions (VIMs) of the OC3 spar-type floating offshore wind turbine (FOWT). Particulars of this research are to investigate the unique and crucial effects of wind load on the spar-type FOWT, which differs considerably from other traditional spar-type floating systems utilized in the gas and oil industry, on the VIMs. The model test was performed with a sequence of current, wind, and irregular wave sea states to analyze the nature of the coupled dynamic response behavior of VIMs. Many unique characteristics were found and analyzed. The lock-in phenomenon of sway in the cross flow (CF) direction was found to occur first, followed by the lock-in phenomenon of surge in the in-line (IL) direction. For the current-only case, the remaining responses, including the other 4-degree-of-freedom motions, mooring tensions, and turbine bearing loads, were found to be coupled by sway/surge VIMs. Moreover, the oscillation amplitudes of all of the responses increased significantly with increasing current velocity, particularly after locking-in. Furthermore, the wind load had a clear suppression effect on the CF and IL VIM responses. The experimental measurements demonstrated that the wave load excites wave-induced oscillations for some CF responses and all IL responses, and it further restrains the VIM oscillation amplitudes on the foundation of the wind suppression effect. In particular, when a wind load is involved, the influence of current or wave is limited to the yaw and IL tower-top bending moment.
Author(s): Duan F, Hu Z, Wang J
Publication type: Article
Publication status: Published
Journal: Journal of Renewable and Sustainable Energy
Online publication date: 03/11/2016
Acceptance date: 19/10/2016
Date deposited: 03/11/2016
ISSN (electronic): 1941-7012
Publisher: A I P Publishing LLC
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