Floating Foundations for Offshore Wind Turbines

The concept of harnessing the power of the wind dates all the way back to the first ships traversing the seas. Later, windmills enabled the use of wind power for industrial purposes. Since then, technology has allowed the production of clean renewable energy through the use of wind turbines. These turbines have traditionally been placed on land, but several factors have urged a move to offshore locations. Now the boundaries are being pushed into deeper and deeper waters, where the idea of floating offshore wind turbines has emerged. In less than a decade, these have gone from scattered small-scale prototypes to full-scale pre-commercial wind parks.

This thesis explores different aspects of numerical and physical modeling of floating offshore wind turbines. Numerical investigations, validated by physical test data, are used to highlight some of the implications of modeling these highly coupled aero-hydro-servo-elastic systems. The proper dynamic numerical modeling of floating offshore wind turbines is one of the key aspects in increasing the feasibility of the sector. For experimental testing and development, a novel system for thrust load emulation has been designed and presented. This system enables cheaper early-stage physical prototype testing in wave basins without wind generating capabilities, and hence allows testing of a wider range of concepts.