Implementation and validation of a hydrodynamic analysis model in the BEMUse library for floating platforms

The ambitious goal set at the Climate Conference in Paris in 2015 (COP21) to try and contain the world’s average temperature increment below 1.5 °C with respect to the pre-industrial era requires the introduction of more efficient and productive technologies for the exploitation of renewable energy sources in all their forms. Among these technologies, wind power is at the moment one of the most reliable and advanced, as it’s been effectively operating for decades now. Wind turbines are currently scattered all around the world both on land and at sea. Finding a suitable installation site on land is becoming increasingly difficult in a lot of countries though, a factor which has increased the interest for offshore solutions in recent years. Unfortunately, current technology has quite strict requirements when it comes to the choice of a suitable site, specifically on the water depth. To increase the exploitable surface for wind energy production, the concept of floating offshore wind turbines (FOWTs) has recently gained increasing interest in the sector. As the name suggests, wind turbines are in this case mounted on floating platforms instead of being anchored to the seafloor. This solution increases enormously the sea surface suitable for wind farms, but at the same time requires accurate simulations of the behavior and performance of the turbines, when subjected to forces and motions caused by both waves and wind. This analysis requires precise and reliable hydrodynamic analysis softwares like WAMIT and Ansys AQWA. At the Technische Universität Berlin, a new such model called BEMUse has been developed and needs to be validated. In this thesis, the results given by BEMUse are compared with the ones obtained with the two softwares mentioned before for a set of geometries ranging from a simple hemisphere to prototypes of platforms of great interest for commercial installations. The comparison will examine four crucial hydrodynamic parameters: added mass, radiation damping, exciting forces, and Response Amplitude Operators (RAOs). If the results agree, BEMUse can be considered validated and can be used as an alternative to expensive softwares like WAMIT.