<p>Design optimization of mooring systems is an important step towards the reduction of costs for the floating wind turbine (FWT) industry. Accurate prediction of slowly-varying motions in surge and sway is needed, but there are still questions regarding the most adequate models for low-frequency wave excitation, and damping, for typical FWT concepts. To fill this gap, it is fundamental to compare existing load models against model tests results. This paper describes a calibration procedure for a three-columns semisubmersible FWT, based on adjustment of a time-domain numerical model to experimental results in decay tests, and tests in waves. The procedure consists in two main steps. First, the numerical model is verified, to check convergence of the panel model, and of the frequency- and time-domain solutions. The model is then validated against experimental data, such that the adequate load models are chosen and adjusted, considering uncertainties related to inertia, wave drift loads, and damping. In this step, Newman's approximation is adopted for the second-order wave loads, using wave drift coefficients obtained from the experiments. Viscous damping is initially determined as a combination of linear + quadratic model, based on decay tests. Additional damping from waves is then adjusted for each sea state, consisting of a combination of a wave drift damping component, and one component with viscous nature. Finally, a parameterization procedure is proposed for generalizing the results to sea states not considered in the tests.</p>

Calibration of a Time-Domain Hydrodynamic Model for a 12 Mw Semisubmersible Floating Wind Turbine

Paper Proceedings: https://asmedigitalcollection.asme.org/OMAE/OMAE2021/volume/85116

OMAE 2021

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