Causality-Free Modeling and Validation of a Semisubmersible Floating Offshore Wind Turbine Platform With Tuned Mass Dampers

This article introduces an acausal modeling approach for constructing a hydrodynamic module within the Control-oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), a wind turbine simulator under development by the authors, to facilitate control codesign (CCD) for floating offshore wind turbines. Verification and validation of the model are conducted using numerical data from the industrial-standard simulation platform OpenFAST and experimental data from the Floating Offshore-wind and Controls Advanced Laboratory Project. The validation results highlight the qualitative ability of the hydrodynamic module in CRAFTS to accurately capture loads and responses under wave excitation, including the stabilizing effects of tuned mass dampers across various load cases. Modeling the VolturnUS-S semisubmersible floater in CRAFTS, known for its complexity compared to other floaters like spar-buoy or tension leg platforms, demonstrates the versatility of this modeling approach for different support structures. Furthermore, runtime simulation comparisons reveal the enhanced computational efficiency of CRAFTS compared to OpenFAST, indicating significant improvements and underscoring its suitability for CCD applications.