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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).
This paper presents a coupled dynamic motion response analysis of a floating wind turbine using an inhousecode, CRAFT (Coupled Response Analysis of Floating wind Turbine). Viscous drag forces on horizontalpontoons are carefully calculated, and a nonlinear spectral method is applied to efficiently solvethe coupled tendon dynamics. Viscous drag forces and tendon dynamics are two important factors whenassessing a tension-leg platform (TLP)-type floating wind turbine in a time-domain simulator. Theanalysis object is the NREL 5 MW Wind Turbine, which is supported by a three-leg mini-TLP platform.Simulations of the free decay and response amplitude operator (RAO) tests are conducted using CRAFT aswell as FAST, another commonly used code. The obtained results are compared with experimental resultsto verify the capability of CRAFT. Viscous drag force induces higher harmonic pitch resonance, which ismost prominent when the wave period is three times the natural period of the pitch and the wave heightreaches a threshold. Springing motion is identified and found to be caused by this resonant pitch motion.Time-domain statistics show that extreme increases in tendon loads caused by springing as well as pitchand tendon tension probability distributions are non-Gaussian in random sea states. In addition, theresonant pitch motion is significantly reduced by aerodynamic damping.
Author(s): Shen M, Hu Z, Liu G
Publication type: Article
Publication status: Published
Journal: Renewable Energy
Print publication date: 01/12/2016
Online publication date: 01/08/2016
Acceptance date: 21/07/2016
Date deposited: 11/10/2016
ISSN (print): 0960-1481
ISSN (electronic): 1879-0682
Publisher: Pergamon Press
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