Hydrodynamic analysis and mooring design of a floating pitching Wave Energy Converter

The work presented in this thesis is part of an integrated research carried out for the development of the ISWEC technology. The key aspects of this WEC that can experience relevant improvement for the technology design and optimization are found to be hydrodynamics modelling and mooring design. These two topics are investigated in order to achieve a high reliability numerical tool for the performance analysis and testing of the ISWEC device. The existing numerical model has been upgraded and validated against experimental results, introducing non-linear phenomena. A mooring system has been designed to be general, considering all the requirements needed for the device deployment. A design procedure has been used according to offshore conservative standards, to guarantee the feasibility of the project. The survivability of the moored device has been tested in a wave tank, reproducing the full storm duration for a severe installation site. Different mooring configurations have been tested and the best one has been identified. The two experimental campaigns have been carried out in Napoli, at the towing tank of the Department of Industrial Engineering of Università degli studi di Napoli Federico II. Methodologies and results presented in this thesis will be used for the design and deployment of a new ISWEC prototype to be installed in the next future. The tools and methodologies here presented can be considered as general and used for the development of different floating WECs. More in detail, the mooring study is useful for all the floating and submerged WECs that require slack mooring systems. On the other hand, the hydrodynamic aspect analyzed in this work are common to the majority of point absorber WECs, with a particular relevance for WECs that exploit pitch or roll motions.