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Lookup NU author(s): Professor Zhiqiang Hu
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
Several floating wind turbine designs whose hull designs reflect those used in offshorepetroleum industry have emerged as leading candidates for the future development ofoffshore wind farms. This article presents the research findings from a model basin testprogram that investigated the dynamic response of a 1:50 scale model OC3 spar floatingwind turbine concept designed for a water depth of 200 m. In this study the rotor wasallowed to rotate freely with the wind speed and this approach eliminated some of theundesirable effects of controlling wind turbine rotational speed that were observed inearlier studies. The quality of the wind field developed by an array of fans was investigatedas to its uniformity and turbulence intensity. Additional calibration tests were performedto characterize various components that included establishing the baseline wind turbinetower frequencies, stiffness of the delta type mooring system and free decay responsebehaviour. The assembled systemwas then studied under a sequence of wind and irregularwave scenarios to reveal the nature of the coupled response behaviour. The wind loadswere found to have an obvious influence on the surge, heave and pitch behaviour of thespar wind turbine system. It was observed from the experimental measurements thatbending moment at the top of the support tower is dominated by the 1P oscillationcomponent and somewhat influenced by the incoming wave. Further it was determinedthat the axial rotor thrust and tower-top shear force have similar dynamic characteristicsboth dominated by tower’s first mode of vibration under wind-only condition whiledominated by the incident wave field when experiencing wind-wave loading. The tensionsmeasured in the mooring lines resulting from either wave or wind-wave excitations wereinfluenced by the surge/pitch and heave couplings and the wind loads were found to havea clear influence on the dynamic responses of the mooring system.
Author(s): Duan F, Hu Z, Niedzwecki J
Publication type: Article
Publication status: Published
Journal: Marine Structures
Print publication date: 01/09/2016
Online publication date: 02/06/2016
Acceptance date: 25/05/2016
Date deposited: 11/10/2016
ISSN (print): 0951-8339
ISSN (electronic): 1873-4170
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