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Coupled Systems Mechanics Volume 1, Number 3, September 2012 , pages 247-268 DOI: https://doi.org/10.12989/csm.2012.1.3.247 |
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Dynamic response analysis of floating offshore wind turbine with different types of heave plates and mooring systems by using a fully nonlinear model |
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Muhammad Bilal Waris and Takeshi Ishihara
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| Abstract | ||
| A finite element model is developed for dynamic response prediction of floating offshore wind turbine systems considering coupling of wind turbine, floater and mooring system. The model employs Morison\'s equation with Srinivasan\'s model for hydrodynamic force and a non-hydrostatic model for restoring force. It is observed that for estimation of restoring force of a small floater, simple hydrostatic model underestimates the heave response after the resonance peak, while non-hydrostatic model shows good agreement with experiment. The developed model is used to discuss influence of heave plates and modeling of mooring system on floater response. Heave plates are found to influence heave response by shifting the resonance peak to longer period, while response after resonance is unaffected. The applicability of simplified linear modeling of mooring system is investigated using nonlinear model for Catenary and Tension Legged mooring. The linear model is found to provide good agreement with nonlinear model for Tension Leg mooring while it overestimates the surge response for Catenary mooring system. Floater response characteristics under different wave directions for the two types of mooring system are similar in all six modes but heave, pitch and roll amplitudes is negligible in tension leg due to high restraint. The reduced amplitude shall lead to reduction in wind turbine loads. | ||
| Key Words | ||
| floating offshore wind turbine; coupled system; Morison equation; finite element | ||
| Address | ||
| Muhammad Bilal Waris : Department of Civil and Architectural Engineering, Sultan Qaboos University, P.O.Box 33, Muscat 123, Sultanate of Oman Takeshi Ishihara : Department of Civil Engineering, School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan | ||
