Dynamic Modelling and Analysis of Three Floating Wind Turbine Concepts with Vertical Axis Rotor

摘要

Recently there is an increasing interest in the development of offshorefloating vertical axis wind turbines (FVAWTs). A FVAWT mountedon a semi-submersible has been proposed by several researchers, and aFVAWT with a spar buoy has been studied comprehensively in the EUproject DeepWind. However, few studies of FVAWT with a TLPfloater has been conducted and limited comparative study of FVAWTwith different supporting structure has been carried out. In this study, aFVAWT with 5MW Darrieus rotor was used as the reference windturbine and mounted on three different floating support structures – theOC3 spar buoy, the OC4 semi-submersible and a TLP. Fully couplednonlinear time domain simulations using the state-of-the-art codeSimo-Riflex-DMS were conducted. A series of load cases withturbulent wind and irregular waves were carried out to investigate thedynamic responses of these three FVAWT concepts, such as thegenerator power production, the platform motions, the tower basebending moments and the mooring line loads. 2P effects are prominentfor the three FVAWT concepts. The spar and the semi-submersible canhelp to mitigate the 2P effects on structural loads and mooring linetensions, at the cost of larger platform motions. The TLP is not a goodsubstructure unless the variation of aerodynamic loads is significantlyreduced. The results demonstrate the characteristics of dynamicresponses for each FVAWT concept, reveal their advantages andfeasibilities and will serve as basis for further developments of theFVAWTs.