Dissertation for the Degree of Master of
Naval Architecture and Marine Engineering
President: Supervisor: Co-supervisor: Member: Prof. Yordan Garbatov Prof. Carlos António Pancada Guedes Soares Dr. Debabrata Karmakar Prof. Serge Sutulo
Dedicated to Teresa Leonor Lopes Miranda
I express my sincere thanks and appreciation to my supervisor Professor Carlos Guedes Soares for his guidance, supportand help during the tenure of the present research work. I am highly indebted to Professor Carlos Guedes Soares who has taken keen interest and offered valuable suggestions on the research work. I feel proud and honored to be a student of such a personality. I sincerely appreciate and thank Dr Debabrata Karmakar for his co-operation and help right from the inception of the problem to the finalpreparation of the manuscript. Thanks are also to the all the faculty members of the CENTEC for their technical suggestions at various times. My thanks are also to my colleagues and other labmates for their active cooperation with whom I shared so many nice moments together. Lastly, I extend my sincerest gratitude to my parents and brothers for always standing by me and supporting me at this endeavor.Hasan Bagbanci
A detailed study on offshore floating wind turbines and the working principle of various floater concepts and the conceptual designs for floating platforms used for floating wind turbines are presented. In the case of fixed windturbine, the influence of the environmental conditions on wind turbine design loads for a monopole foundation is studied by analyzing the bending moment at the tower base and tower root for various values of water depth, tower height, pile diameter and turbulence model. The analysis is done using FAST code for 5MW wind turbine with a monopile foundation. In the study of offshore floating windturbine, a numerical time-domain model is used for the fully coupled dynamic analysis of deep water offshore floating wind turbines such as spar-type, barge-type and semi-submersible-type floating wind turbine. The
hydrodynamic behaviour of the floaters is analysed using panel method. Hydrodynamic added mass, damping and exiting force are obtained in frequency domain and are validated with theavailable results. The hydrodynamic study of the floater is combined with and aerodynamic model to obtain a coupled aero-servo-hydro-elastic model. The performance of spar-type and barge-type floating wind turbine designed by the National Renewable Energy Laboratory (NREL) and semi-submersible type floating wind turbine designed by Principle Power are analyzed in detail. The mooring system attached toWindFloat semi-submersible floating wind turbine is also examined for six and eight mooring lines and the platform rotations along with motions results obtained are also compared. Keywords: Renewable energy; Monopile wind turbine; Offshore floating wind turbine; Added mass; Damping coefficient; Mooring system.
Um estudo detalhado sobre mar turbinas eólicas flutuantes e o princípio de funcionamento de conceitos diversos floater e os projetos conceitual para plataformas flutuantes utilizadas para turbinas eólicas flutuantes são apresentados. No caso da turbina de vento fixo, a influência das condições ambientais em cargas de turbinas eólicas de...