Unstructured meshes calculation method for reponse amplitude operators of TLP wind turbines

H F Wang, Y H Fan

COMPUTER MODELLING & NEW TECHNOLOGIES 2014 18(12D) 289-295

School of Natural Sciences and Humanities, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong Province, 518055, China

Here we propose a new method for calculating the pitch Response Amplitude Operators (RAOs) for a Tension Leg Platform (TLP) wind turbine. The traditional method is limited for finding the stability of a body in water; the traditional method is also limited regarding the development requirement of worldwide floating offshore wind energy. The TLP is modeled and meshed in GID software, and a time domain analysis at a particular wind speed was carried out using FEM analysis on an unstructured mesh (UM-FEM). The calculations of mass and hydrodynamic matrices are discussed in detail. Also, translation of these matrices from the origin, which is typically on the free surface of a body of water, to the center of gravity for the platform is discussed in detail. Finally, a linear analysis of a mooring system is discussed, and pitch RAOs were calculated and validated against prior data. The result from the proposed new method closely fits the NREL results and reaches the same conclusion as other studies. This implies that this computation process is correct and that this new method can be used with low error and in conjunction with other methods for offshore wind energy generation applications.