| Summary: | Wind turbines are mainly classified into horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs) based on different orientation of their axis of rotation. Ever-increasing demand for energy boosts the application of the wind turbines in the deep water. The applications of HAWTs in deep water using different floating support structures have led to an increasing and versatile research due to their commercial success. However, the application of the VAWTs in the offshore wind industry also has some potential due to its economical installation and maintenance. More and more efforts have been invested in developing floating vertical axis wind turbines (FVAWTs), but the research on the FVAWTs is still at an early stage. Although different concepts of the FVAWTs were proposed based on a combination of a rotor and a floater, an optimized design is still an open question. The rotor covers straight-blade rotor, Darrieus curved-blade type rotor and helical-blade rotor while a floater could be a spar, semi-submersible or tension leg platform (TLP). To evaluate a FVAWT, a simulation tool is needed to perform time domain numerical simulations. The simulation tool should have the capability to calculate aerodynamic loads on the rotor, hydrodynamic loads on the floater and structural dynamics of the rotor, and include a controller. Based on the calculated dynamic response, a response analysis is carried out to better understand the response characteristics of a FVAWT as a basis for design and safety criteria according to serviceability. The objective of this thesis has been the development of a coupled method for integrated dynamic analysis of the FVAWTs and application in a systematic study of a Darrieus rotor on a semi-submersible floating support structure. The aerodynamic analysis of a VAWT differs from that of a HAWT, especially when the VAWT is mounted on a floater. Thus, the aerodynamics of a VAWT is first addressed and a model improvement for evaluating the effect of tower tilting on the ...
|
|---|