Computational Fluid Dynamics Application in Renewable Energy and Offshore Mechanics
| The use of wind turbines on land to produce electricity is now fairly well established. However, places best suitable for land-based wind-turbines, such as the plains of the Midwest United States, are often located far from densely populated areas along the coasts, and concerns about the negative visual impact of wind-turbines on attractive natural landscapes have been raised. Many off-shore, bottom mounted wind turbines have been constructed in shallow waters (less than 30 meter depth) in Europe. The wind is usually stronger and steadier for these installations, but objections about the visual impact of shallow water wind farms on coastal landscapes and properties have delayed development in the US (Cape wind project is an example). |
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| Placing floating wind turbines far offshore, in deep water, avoids many of the concerns of land-based and shallow water wind turbines and can be the key solution to furthermore harvest the wind energy.Due to the complexity of design and high cost of intallation, limited number of large large-scale floating wind turbines have been bulit so far. Those include two turbines deployed off the coast of Norway, one by Statoil called Hywind and another one called SWAY. In addition, the Blue H has been tested off the coast of Italy, and Energias de Portugal and Principle Power Inc. have recently deployed a full-scale 2 MW WindFloat platform off the coast of Portugal. Numerical studies focused on modeling the response of different designs to operational and extreme loads are relatively recent, and have used either linear frequency-domain (LFD) analysis or time-domain dynamics (TDD) models; or a combination of both which have some limitations (see for example this paper by Jonkman). |
5 MW TLP in interaction with wind and wave |
| In order to overcome the current limitations, a nonlinear computational model for the dynamic motion of floating wind turbines is developed. The model includes advanced CFD three dimensional techniques for studying interaction of floating wind turbine platforms with waves and reduced order dynamical models for considering rotor, nacelle, and the mooring system, resulting in an efficient numerical approach which can handle nearly all the nonlinear hydrodynamic forces on the platform, while imposing no limitation on the platform motion. The developed numerical model is used for simulation of a spar buoy and a tension leg platform. | |
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5 MW spar buoy floating wind turbine in interaction with random waves |
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