For wind to play a significant role in meeting the energy need of the US two considerations must be accounted for: The energy must be generated close to where it is needed and it can only be generated where the wind blows. The energy is needed in cities on the costs and the wind blows more steadily off shore. Wind turbines placed in shallow ocean water on rigid platforms do however raise environmental concerns and may degrade the natural beauty of beaches and coastlines. These concerns often lead to significant delays in construction and installation. Floating, far-offshore wind turbines, located farther from land in deep water, would eliminate these environmental concerns, while at the same time tapping into even greater wind power potential. While the potential for floating wind turbines is vast, they pose major engineering challenges. Not only must the turbines be stable and structurally sound when forced by large ocean waves, they must also be economical to build. The present study will develop integrated computer simulations and physical experiments to advance the state-of-the-art in modeling of floating wind turbines located in deep ocean water. The results will help us understand how such platforms behave, thus making it possible to design economical wind turbines. The intellectual merit of the proposed activity is to lay the foundation for understanding how floating platforms behave by developing numerical simulations with sufficient accuracy for the early design stages where the overall character of the system are established. In effect we will develop a "numerical" offshore water tank, and then validate the numerical simulations with physical experiments. The broader impact of the proposed activity is that it advances the nation's capabilities in a new renewable energy technology by developing multi-scale computational tools and physical experiments to model a complex system subject to extreme environmental loads. The need for multiscale modeling capability is needed in a broad range of applications and the success of the present project will have wide impact for related problems.
