Floating vertical axis wind turbines (VAWTs) are still in the early stages of development

lacking dedicated platform designs and insufficient research on their aerodynamic- hydrodynamic coupling. To investigate the dynamic response characteristics of floating VAWTs under combined wind and wave loads

this study focuses on a Spar-type VAWT

which is currently in the technological exploration and engineering validation phase. A full-scale numerical model of a large floating VAWT based on the Spar platform is established

and computational fluid dynamics (CFD) methods are employed to study the coupled aerodynamic-hydrodynamic-mooring dynamics under wind-wave conditions. The results show that

under wind-wave loads

floating VAWTs exhibit a higher average power coefficient than fixed-bottom VAWTs

but with more intense fluctuations in the power coefficient response. The lateral force generated by rotor rotation under wind loads increases the sway amplitude

leading to alternating

opposing oscillation patterns in mooring lines 2 and 3. Additionally

the pitch response significantly affects the power coefficient and wake characteristics of floating VAWTs.