Abstract
The dynamic responses of INO WINDMOOR Floating Wind Turbine (FWT) in low frequency surge motion is investigated as a case study. A set of environmental conditions is selected to represent operational conditions with aligned wind and waves. The relative contribution of waves, as well as wind, low frequency excitations to the low frequency horizontal motion of the floating wind turbine is investigated. Simulations are conducted for turbulent wind and irregular waves with an aero-hydro-servo-elastic computational tool with the state-of-the-art force models. The effect of increasing wind speed in turbine’s operational range, in presence of low and moderate sea states, is studied in terms of low frequency surge motion of the platform. A detailed comparison for a moderate sea-state and rated wind speed is presented, where the effect of waves on slowly varying surge motion is discussed. The combined wind and wave contributions to the turbine aerodynamic damping is considered. The additional low frequency damping in surge due to wave frequency motions of hull and mooring lines are investigated. It is shown that the aforementioned damping could contribute to reduction of the response spectrum in the vicinity of the surge natural frequency. Further investigations are proposed to form a better understanding of wave and wind relative contributions to slowly varying motions.