OC6 Phase Ib: Validation of the CFD predictions of difference-frequency wave excitation on a FOWT semisubmersible

Authors

• Lu Wang, National Renewable Energy Laboratory
• Amy Robertson, National Renewable Energy Laboratory
• Jason Jonkman, National Renewable Energy Laboratory
• Yi Hsiang Yu, National Renewable Energy Laboratory
• Arjen Koop, Maritime Research Institute Netherlands
• Nadal A Borràs
• Haoran Li, Norwegian University of Science and Technology
• Erin Bachynski-Polić, Norwegian University of Science and Technology
• Romain Pinguet, Aix-Marseille Université
• Wei Shi, Dalian University of Technology
• Xinmeng Zeng, Dalian University of Technology
• Yang Zhou, University of Strathclyde
• Qing Xiao, University of Strathclyde
• Rupesh Kumar, University of Ulsan
• Hamid Sarlak, Technical University of Denmark
• Edward Ransley, School of Engineering, Computing and Mathematics
• Scott Brown, School of Engineering, Computing and Mathematics
• Martyn Hann, School of Engineering, Computing and Mathematics
• Stefan Netzband, Hamburg University of Technology
• Malwin Wermbter, Hamburg University of Technology
• López B Méndez

ORCID

• Edward Ransley: 0000-0003-1446-7907
• Scott Brown: 0000-0002-6858-3316
• Martyn Hann: 0000-0003-3965-9331

Document Type

Article

Abstract

During the previous OC511 project, state-of-the-art mid-fidelity engineering tools for floating wind systems were found to consistently underpredict the nonlinear, low-frequency responses of semisubmersible offshore wind platforms, leading to substantial errors in the structural loads because of low-frequency surge and pitch resonance. To examine this underprediction, a coordinated investigation with computational fluid dynamics (CFD) simulations and model-basin experiments was carried out. Both investigations involved a fixed and simplified OC5-DeepCwind semisubmersible in bichromatic waves. The wave excitations—especially the nonlinear, difference-frequency excitation—on the structure from the CFD simulations were compared to the experimental measurements for validation, with uncertainty analyses for both the experimental and the CFD results. Further, the wave excitations on each column of the semisubmersible were measured separately in the experiment, allowing the validation of the CFD results to be done on a per-column basis. Overall, the CFD predictions of the difference-frequency excitations agree with the experimental measurements, suggesting the CFD solutions can be used as a reference for tuning and improving the engineering-level tools and can provide a means to better understand the underprediction at low frequencies.

DOI Link

10.1016/j.oceaneng.2021.110026

Publication Date

2021-12-01

Publication Title

Ocean Engineering

Volume

241

ISSN

0029-8018

Acceptance Date

2021-10-12

Deposit Date

2021-10-29

Embargo Period

2022-10-27

Funding

This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Wind Energy Technologies Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government.

Keywords

Offshore wind, Bichromatic wave, CFD, Nonlinear excitation, Validation, OC6

Recommended Citation

Wang, L., Robertson, A., Jonkman, J., Yu, Y., Koop, A., Borràs, N., Li, H., Bachynski-Polić, E., Pinguet, R., Shi, W., Zeng, X., Zhou, Y., Xiao, Q., Kumar, R., Sarlak, H., Ransley, E., Brown, S., Hann, M., Netzband, S., Wermbter, M., & Méndez, L. (2021) 'OC6 Phase Ib: Validation of the CFD predictions of difference-frequency wave excitation on a FOWT semisubmersible', Ocean Engineering, 241. Available at: 10.1016/j.oceaneng.2021.110026