OC6 Phase Ia: CFD Simulations of the Free-Decay Motion of the DeepCwind Semisubmersible

OC6 Phase Ia: CFD Simulations of the Free-Decay Motion of the DeepCwind Semisubmersible

Wang, Lu (National Renewable Energy Laboratory)
Robertson, Amy (National Renewable Energy Laboratory)
Jonkman, Jason (National Renewable Energy Laboratory)
Kim, Jang (Front Energies)
Shen, Zhi‐Rong (Front Energies)
Koop, Arjen (Marin)
Chandramouli, P. (TU Delft Wind Energy)
Viré, A.C. (TU Delft Wind Energy)
Ramesh Reddy, L. (TU Delft Wind Energy)

2022

Currently, the design of floating offshore wind systems is primarily based on mid-fidelity models with empirical drag forces. The tuning of the model coefficients requires data from either experiments or high-fidelity simulations. As part of the OC6 (Offshore Code Comparison Collaboration, Continued, with Correlation, and unCertainty (OC6) is a project under the International Energy Agency Wind Task 30 framework) project, the present investigation explores the latter option. A verification and validation study of computational fluid dynamics (CFD) models of the DeepCwind semisubmersible undergoing free-decay motion is performed. Several institutions provided CFD results for validation against the OC6 experimental campaign. The objective is to evaluate whether the CFD setups of the participants can provide valid estimates of the hydrodynamic damping coefficients needed by mid-fidelity models. The linear and quadratic damping coefficients and the equivalent damping ratio are chosen as metrics for validation. Large numerical uncertainties are estimated for the linear and quadratic damping coefficients; however, the equivalent damping ratios are more consistently predicted with lower uncertainty. Some difference is observed between the experimental and CFD surge-decay motion, which is caused by mechanical damping not considered in the simulations that likely originated from the mooring setup, including a Coulomb-friction-type force. Overall, the simulations and the experiment show reasonable agreement, thus demonstrating the feasibility of using CFD simulations to tune mid-fidelity models.

CFD
validation
free decay
offshore wind
semisubmersible
uncertainty
OC6
IEA
Free decay
Validation
Uncertainty
Semisubmersible
Offshore wind

http://resolver.tudelft.nl/uuid:66a6b145-9370-49ec-864f-95c1ff470563

https://doi.org/10.3390/en15010389

1996-1073

Energies, 15 (1)

Institutional Repository

journal article

© 2022 Lu Wang, Amy Robertson, Jason Jonkman, Jang Kim, Zhi‐Rong Shen, Arjen Koop, P. Chandramouli, A.C. Viré, L. Ramesh Reddy, More Authors