Dynamic Response Analysis Of A Spar Type Floating Wind Turbine Platform

With increasingly serious energy scarcity and global warming, wind energy, as agreen and renewable energy, attracts more and more attentions. Because the space forland wind farms is limited and near shore wind farms would affect coastalenvironment, wide installing space and enormous wind energy in deep sea haveattracted more and more experts to devote themselves to carrying out research onfloating offshore wind turbines (FOWT).Firstly, this thesis reviews the previous domestic and overseas researches onFOWT foundations, summarizes the theories to calculate wind and wave loads andintroduces the methods to calculate floating structures’ responses in frequency andtime domain respectively.On that basis, a panel model of the Spar-type OC3-Hywind FOWT is establishedvia the Patran-Pre module in the software SESAM. Calculations of added mass,potential damping, RAOs and exciting forces are carried out using HydroD module.Then under the environmental conditions the FOWT may encounter in operativemode and with the coupled interactions between the Spar platform and the mooringlines being taken into consideration, calculations are implemented for static positionsof the anchored FOWT in steady winds of mean speed and the system’s dynamicresponse in the regular waves and irregular waves with mean speed steady winds.Through the power spectrum analysis of the results in time domain, it is concludedthat the anchored platform’s motions can be divided into a low frequency part relatedto the mooring lines and the platform’s natural frequency and a high frequency partrelated to the wave encounter frequencies. Meanwhile, through the maximum analysisof the results in time domain, it is concluded that the platform’s motions aredetermined by the wind forces and the wave encounter frequencies acting on theFOWT. The amplitudes of the platform’s motions increase with the increase of windforces and wave encounter periods.The present research method of coupled dynamic response analysis for FOWTmay give some reference to the future researches in this area. The results of thepresent study may provide some guidance to the design improvements of FOWT andsome reference to the related experimental studies in the future.