CFD analysis of a Floating Offshore Wind Turbine

2020 is a year that we will hardly forget. It has been the year of the Pandemic, the year in which we understood that nothing can be taken from granted, included our future. Sustainability must be the key and the European Union is strongly pushing towards it. In fact, order to receive part of the Next Generation EU fund, the member states need to present a recovery plan that reflects EU missions, one of which is the Ecological transition. In June 2021, Italian Ministry on Ecological Transition has declared the official interest in the development of the renewable energy coming from the Floating Offshore Wind Turbine. Due to the sea depth and the high potential of Wind Energy in the Mediterranean Sea, this kind of renewable energy is the most suitable for wind exploitation. The blocking points towards this kind of renewable energy source are mainly linked to the high cost of energy (LCOE) and to the absence of a reliable model for a primary analysis. This thesis work is focused on the second one. Starting from a NREL 5MW Wind Turbine and the environmental data of a selected site near Pantelleria Island, the aim is to create a reliable model of a Wind Turbine for a Computational Fluid Dynamics analysis. To find the best simulation, the first step is to perform the convergence study of the mesh by using four decreasing mesh sizes. Once mesh is defined, the best result is searched by comparing simulation results as a function of simulation parameters, such as: domain dimensions, time-steps, overall simulation time, computational cost. The values that will define the validity of the model and that will be the subject of the Post-Processing phase are the Torque $M_x$ and the Drag $F_x$. As it was not possible to collect experimental data, the numerical error is computed by comparing their values to those obtained through BEM. For future works, the model of the complete Floating Wind Turbine should be used, by adding the Tower, Floater and Moorings. The Validation and Verification phase of CFD analysis should be completed by the use of experimental data coming from also these parts.