Sist, Nicolas David
Hydrodynamic model for a semi-submersible floating wind turbine
Wednesday 20th July 2011
In the last years the importance of wind power has been continuously increasing. Although onshore wind turbines can deliver energy at about half the cost of typical new offshore wind farms, offshore wind power is now widely expanding due to the more space in the ocean, better wind resources and fewer restrictions with respect to noise and visual impact. For depths larger than 80 m, floating wind turbine foundations become feasible compared to bottom fixed solutions. The aim of this thesis is to study the motion of a particular floating wind turbine concept. To achieve this goal we derive the motion equations of a generic floating structure subjected to some forces restraints. Different kind of forces which can eventually act on a floating body are treated, namely wave forces, mooring forces and damping forces due to heave plates. Some tests on simple geometric shapes are then implemented to check the validity of both the theory introduced and of the numerical methodology developed. The last part is dedicated to the description of the floating wind turbine and to numerical results of its motion in different configurations.