Hull and mooring design of gyroscopic-based wave energy converter

Wave energy is one of the less exploited, yet potentially more interesting renewable energy source. In a world where the energy consumption is constantly increasing, but economic and environmental reasons drive the research of alternatives to not-renewable energy sources, it’s just a matter of time before wave energy become an economically sustainable source of renewable energy. The research effort, started in the seventies, was focused on the development of devices for the harvesting of energy from the energetically rich seas of northern Europe. The work presented in this thesis is focused on the development of ISWEC, a wave energy converter based on a gyroscopic conversion of a hull motion, designed specifically to work in the Mediterranean Sea. The device, described in detail in chapter 3, was designed in the Department of Mechanics of the Polytechnic of Turin since 2005, and I worked within the research group responsible for its development. Design of a wave energy converter requires understanding the complex interactions between the device, and its energy-harvesting system, and the waves of the sea. This can be done by the use of numerical models, but experimental validation and testing are always necessary to gain a complete knowledge of such complex phenomena. A substantial part of my work was dedicated to experimental analysis of ISWEC: chapter 4 describes the analysis conducted on the 1:8 scaled model of the device, in order to adjust and validate a numerical model able to describe the device behavior. Results obtained from the experimental campaign on the 1:8 model have been used to design the hull of the full scale prototype of the device, as described in chapter 5. Chapter 6 is dedicated to the study conducted on the mooring system for ISWEC, again performed with the aid of an extensive campaign of tests on a 1:50 scaled model of the device, and of its mooring system.