OC6 Phase Ia : CFD simulations of the free-decay motion of the DeepCwind semisubmersible

Enthalten in
Energies 
Volume
15
Issue
1
Article Number
389
Citation
Energies 15 (1): 389 (2022)
Publisher DOI
10.3390/en15010389
Scopus ID
2-s2.0-85122242879
Publisher
Multidisciplinary Digital Publishing Institute
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.
Schlagworte
CFD
validation
free decay
offshore wind
semisubmersible
uncertainty
OC6
IEA
DDC Class
600: Technik
620: Ingenieurwissenschaften
More Funding Information
Funding for this work was provided in part by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Wind Energy Technologies Office under Contract No. DEAC36-08GO28308. The University of Plymouth team would like to acknowledge the ongoing support of the Engineering and Physical Sciences Research Council (EPSRC) via project EP/T004177/1.
MARIN would like to acknowledge that their contribution is partly funded by the Dutch Ministry of Economic Affairs and Climate Policy. The simulations by the Delft University of Technology team made use of the Dutch national e-infrastructure with the support of the SURF Cooperative with grant no. EINF-1649. The simulations by the Dalian University of Technology team were supported by the
National Natural Science Foundation of China with grant no. 52071058.