Nonlinear effects and dynamic coupling of floating offshore wind turbines using geometrically-exact blades and momentum-based methods

作者：Tang, Shanran; Sweetman, Bert^*; Gao, Ju

来源：Ocean Engineering, 2021, 229: 108866.

DOI：10.1016/j.oceaneng.2021.108866

• Nonlinear dynamics
• Multi-scale coupling
• Momentum-based beam theory
• Momentum cloud method
• Highly-compliant floating wind turbine

Nonlinear blade effects and overall dynamic coupling of floating offshore wind turbines (FOWTs) are investigated using the latest developments in nonlinear beam theory and multibody dynamics. An aerohydro-servo-elastic coupled model is developed combining momentum-based beam theory (MBBT) and the momentum cloud method (MCM) based on a multi-time-scale coupling scheme, in which geometrically-exact blades are coupled with a highly-compliant floating platform design that allows large angular motions. Comprehensive simulations are performed and the results are analyzed to demonstrate the importance of nonlinear effects and dynamic coupling of FOWTs. Nonlinear blade dynamics are shown to be critical in assessments of turbine performance and blade fatigue. The highly-compliant floater design is found to be feasible in realistic operating conditions. A strong one-way dynamic coupling is observed from platform motions to blade vibrations. Axi-asymmetric response of the blades is found to induce significant imbalanced aerodynamic loading onto the turbine and the platform.