Abstract: The time-domain calculation method for the dynamic response of floating wind turbines under the combined action of wind, waves, and flow has been extensively researched and developed. However, due to its low computational efficiency, significant computational resources are required when applying this method to optimize the layout of units in a floating wind farm and to optimize the preliminary design of floating wind turbines and mooring systems. Therefore, this paper focuses on the frequency domain analysis method that can achieve rapid calculation of the dynamic response of floating wind turbines. It comprehensively considers various environmental load factors, including first and second-order wave loads, wind turbine pulsating wind loads, slender member viscous loads, mooring systems, and wind turbine pitch control strategies. For different operating conditions such as rated operation, pitch operation, and shutdown, the results of the frequency domain method were compared and analyzed with the time-domain prediction results from Orcaflex software. Both methods showed good consistency in terms of steady-state response, dynamic response spectra, and statistical values, thus confirming the applicability and accuracy of the frequency domain analysis method in providing reliable reference value for the preliminary design and parameter sensitivity analysis of floating wind turbines. Furthermore, based on the frequency domain method, the influence of wind and wave parameters, second-order wave forces, and the consideration of wind turbine control strategies on the dynamic response characteristics of floating wind turbines was studied.

Key words: floating wind turbine, frequency domain method, load linearization, dynamic response, second-order wave forces