Coupled dynamic analysis of spar-type floating wind turbine under different wind and wave loading

Abstract

In the present study, the coupled dynamic modelling of three different configurations of spar platform is performed using time-domain aero-servo-hydro-elastic simulation. The spar platforms are coupled with 5 MW NREL floating wind turbine and mooring sub-models. The coupled aero-servo-hydro-elastic simulation is performed using the simulation tool FAST with WAMIT as the sub module to obtain frequency domain hydrodynamic characteristics. The major emphasis is given to analyse the Response Amplitude Operators (RAOs) to understand the stability of the structures. The responses are calculated for surge, sway, heave, roll, pitch and yaw motions. The study determines the performance of the structure under the wind load developed for the turbine support structure on analysing the tower base forces and moments. The analysis for three different configurations of spar platform is performed for various environmental conditions of North Sea. The studies observed that the responses of the platforms tend to increase with increase in wind speed and wave height. Further, it is observed that surge and pitch motion is dominant for all the three configurations of spar platform. The present study provides an insight into the power performance, structural integrity and dynamic motions of the floating wind turbine under various operational and survival conditions which help the designers to develop better design standards. © 2021, Sociedade Brasileira de Engenharia Naval.