Numerical simulation of a semi-submersible FOWT platform under calibrated extreme and irregular waves

A robust numerical tool is presented for simulating the hydrodynamic responses of a semi-submersible floating offshore wind turbine (FOWT) platform under highly nonlinear extreme/irregular wave conditions. The investigation covers both short-duration extreme event and long-duration 3-hour irregular wave scenarios, utilizing a coupled CFD-FEM method integrated with an iterative wave adjustment procedure. The discretization uncertainties of the numerical scheme are rigorously quantified under extreme wave conditions. Comprehensive analysis is conducted on both short and long-duration cases. This study underscores the significant influence of waves on platform hydrodynamic responses, which emphasizes the necessity of accurately replicating the target wave in the numerical wave basin. The importance of the wave calibration method is demonstrated, particularly for capturing low-frequency pitch motion of the platform.