skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine

Abstract

This paper summarizes the findings from Phase II of the Offshore Code Comparison, Collaboration, Continued, with Correlation project. The project is run under the International Energy Agency Wind Research Task 30, and is focused on validating the tools used for modeling offshore wind systems through the comparison of simulated responses of select system designs to physical test data. Validation activities such as these lead to improvement of offshore wind modeling tools, which will enable the development of more innovative and cost-effective offshore wind designs. For Phase II of the project, numerical models of the DeepCwind floating semisubmersible wind system were validated using measurement data from a 1/50th-scale validation campaign performed at the Maritime Research Institute Netherlands offshore wave basin. Validation of the models was performed by comparing the calculated ultimate and fatigue loads for eight different wave-only and combined wind/wave test cases against the measured data, after calibration was performed using free-decay, wind-only, and wave-only tests. The results show a decent estimation of both the ultimate and fatigue loads for the simulated results, but with a fairly consistent underestimation in the tower and upwind mooring line loads that can be attributed to an underestimation of wave-excitation forces outside the linearmore » wave-excitation region, and the presence of broadband frequency excitation in the experimental measurements from wind. Participant results showed varied agreement with the experimental measurements based on the modeling approach used. Modeling attributes that enabled better agreement included: the use of a dynamic mooring model; wave stretching, or some other hydrodynamic modeling approach that excites frequencies outside the linear wave region; nonlinear wave kinematics models; and unsteady aerodynamics models. Also, it was observed that a Morison-only hydrodynamic modeling approach could create excessive pitch excitation and resulting tower loads in some frequency bands.« less

Authors:
 [1];  [1];  [1];  [2];  [3];  [4];  [5];  [6];  [6];  [7];  [7];  [8];  [9];  [9];  [10];  [11];  [12];  [13];  [14];  [15] more »;  [16];  [16];  [17];  [18];  [19];  [20];  [21] « less
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Fraunhofer Inst. for Wind Energy and Energy System Technology, Bremerhaven (Germany)
  3. Univ. of Maine, Orono, ME (United States)
  4. Maritime Research Inst., Wageningen (Netherlands)
  5. 4Subsea, Nesbru (Norway)
  6. National Renewable Energy Centre (CENER), Navarra (Spain)
  7. Centre for Marine Technology and Ocean Engineering (CENTEC), Lisbon (Portugal)
  8. DNV GL, Bristol (United Kingdom)
  9. Technical Univ. of Denmark, Lyngby (Denmark)
  10. European Centre of the Netherlands, Petten (Netherlands)
  11. Inst. for Energy Technology (IFE), Kjeller (Norway)
  12. IFP Energies nouvelles, Rueil-Malmaison (France)
  13. PRINCIPIA, Nantes (France)
  14. Politecnico di Milano (Italy)
  15. Siemens PLM, Barcelona (Spain)
  16. Tecnalia, San Sebastian (Spain)
  17. Univ. de Cantabria, Cantabria (Spain). IH Cantabria
  18. Univ. of Ulsan, Ulsan (South Korea)
  19. Univ. of Tokyo (Japan)
  20. Univ. Politecnica de Catalunya (Spain)
  21. WavEC Offshore Renewables, Lisbon (Portugal)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W)
OSTI Identifier:
1416253
Report Number(s):
NREL/JA-5000-68050
Journal ID: ISSN 1876-6102
Grant/Contract Number:
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Energy Procedia
Additional Journal Information:
Journal Volume: 137; Journal Issue: C; Journal ID: ISSN 1876-6102
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; 42 ENGINEERING; floating offshore wind turbine; DeepCwind semisubmersible; numerical modeling; verifcation; validation; IEA Wind

Citation Formats

Robertson, Amy N., Wendt, Fabian, Jonkman, Jason M., Popko, Wojciech, Dagher, Habib, Gueydon, Sebastien, Qvist, Jacob, Vittori, Felipe, Azcona, José, Uzunoglu, Emre, Soares, Carlos Guedes, Harries, Rob, Yde, Anders, Galinos, Christos, Hermans, Koen, de Vaal, Jacobus Bernardus, Bozonnet, Pauline, Bouy, Ludovic, Bayati, Ilmas, Bergua, Roger, Galvan, Josean, Mendikoa, Iñigo, Sanchez, Carlos Barrera, Shin, Hyunkyoung, Oh, Sho, Molins, Climent, and Debruyne, Yannick. OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine. United States: N. p., 2017. Web. doi:10.1016/j.egypro.2017.10.333.
Robertson, Amy N., Wendt, Fabian, Jonkman, Jason M., Popko, Wojciech, Dagher, Habib, Gueydon, Sebastien, Qvist, Jacob, Vittori, Felipe, Azcona, José, Uzunoglu, Emre, Soares, Carlos Guedes, Harries, Rob, Yde, Anders, Galinos, Christos, Hermans, Koen, de Vaal, Jacobus Bernardus, Bozonnet, Pauline, Bouy, Ludovic, Bayati, Ilmas, Bergua, Roger, Galvan, Josean, Mendikoa, Iñigo, Sanchez, Carlos Barrera, Shin, Hyunkyoung, Oh, Sho, Molins, Climent, & Debruyne, Yannick. OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine. United States. doi:10.1016/j.egypro.2017.10.333.
Robertson, Amy N., Wendt, Fabian, Jonkman, Jason M., Popko, Wojciech, Dagher, Habib, Gueydon, Sebastien, Qvist, Jacob, Vittori, Felipe, Azcona, José, Uzunoglu, Emre, Soares, Carlos Guedes, Harries, Rob, Yde, Anders, Galinos, Christos, Hermans, Koen, de Vaal, Jacobus Bernardus, Bozonnet, Pauline, Bouy, Ludovic, Bayati, Ilmas, Bergua, Roger, Galvan, Josean, Mendikoa, Iñigo, Sanchez, Carlos Barrera, Shin, Hyunkyoung, Oh, Sho, Molins, Climent, and Debruyne, Yannick. 2017. "OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine". United States. doi:10.1016/j.egypro.2017.10.333. https://www.osti.gov/servlets/purl/1416253.
@article{osti_1416253,
title = {OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine},
author = {Robertson, Amy N. and Wendt, Fabian and Jonkman, Jason M. and Popko, Wojciech and Dagher, Habib and Gueydon, Sebastien and Qvist, Jacob and Vittori, Felipe and Azcona, José and Uzunoglu, Emre and Soares, Carlos Guedes and Harries, Rob and Yde, Anders and Galinos, Christos and Hermans, Koen and de Vaal, Jacobus Bernardus and Bozonnet, Pauline and Bouy, Ludovic and Bayati, Ilmas and Bergua, Roger and Galvan, Josean and Mendikoa, Iñigo and Sanchez, Carlos Barrera and Shin, Hyunkyoung and Oh, Sho and Molins, Climent and Debruyne, Yannick},
abstractNote = {This paper summarizes the findings from Phase II of the Offshore Code Comparison, Collaboration, Continued, with Correlation project. The project is run under the International Energy Agency Wind Research Task 30, and is focused on validating the tools used for modeling offshore wind systems through the comparison of simulated responses of select system designs to physical test data. Validation activities such as these lead to improvement of offshore wind modeling tools, which will enable the development of more innovative and cost-effective offshore wind designs. For Phase II of the project, numerical models of the DeepCwind floating semisubmersible wind system were validated using measurement data from a 1/50th-scale validation campaign performed at the Maritime Research Institute Netherlands offshore wave basin. Validation of the models was performed by comparing the calculated ultimate and fatigue loads for eight different wave-only and combined wind/wave test cases against the measured data, after calibration was performed using free-decay, wind-only, and wave-only tests. The results show a decent estimation of both the ultimate and fatigue loads for the simulated results, but with a fairly consistent underestimation in the tower and upwind mooring line loads that can be attributed to an underestimation of wave-excitation forces outside the linear wave-excitation region, and the presence of broadband frequency excitation in the experimental measurements from wind. Participant results showed varied agreement with the experimental measurements based on the modeling approach used. Modeling attributes that enabled better agreement included: the use of a dynamic mooring model; wave stretching, or some other hydrodynamic modeling approach that excites frequencies outside the linear wave region; nonlinear wave kinematics models; and unsteady aerodynamics models. Also, it was observed that a Morison-only hydrodynamic modeling approach could create excessive pitch excitation and resulting tower loads in some frequency bands.},
doi = {10.1016/j.egypro.2017.10.333},
journal = {Energy Procedia},
number = C,
volume = 137,
place = {United States},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • As offshore wind projects move to deeper waters, floating platforms become the most feasible solution for supporting the turbines. The oil and gas industry has gained experience with floating platforms that can be applied to offshore wind projects. This paper focuses on the analysis of second-order wave loading on semisubmersible platforms. Semisubmersibles, which are being chosen for different floating offshore wind concepts, are particularly prone to slow-drift motions. The slack catenary moorings usually result in large natural periods for surge and sway motions (more than 100 s), which are in the range of the second-order difference-frequency excitation force. Modeling thesemore » complex structures requires coupled design codes. Codes have been developed that include turbine aerodynamics, hydrodynamic forces on the platform, restoring forces from the mooring lines, flexibility of the turbine, and the influence of the turbine control system. In this paper two different codes are employed: FAST, which was developed by the National Renewable Energy Laboratory, and aNySIM, which was developed by the Maritime Research Institute Netherlands. The hydrodynamic loads are based on potential-flow theory, up to the second order. Hydrodynamic coefficients for wave excitation, radiation, and hydrostatic forces are obtained with two different panel codes, WAMIT (developed by the Massachusetts Institute of Technology) and DIFFRAC (developed by MARIN). The semisubmersible platform, developed for the International Energy Agency Wind Task 30 Offshore Code Comparison Collaboration Continuation project is used as a reference platform. Irregular waves are used to compare the behavior of this platform under slow-drift excitation loads. The results from this paper highlight the effects of these loads on semisubmersible-type platforms, which represent a promising solution for the commercial development of the offshore deepwater wind resource.« less
  • With the intent of improving simulation tools, a 1/50th-scale floating wind turbine atop a TLP was designed based on Froude scaling by the University of Maine under the DeepCwind Consortium. This platform was extensively tested in a wave basin at MARIN to provide data to calibrate and validate a full-scale simulation model. The data gathered include measurements from static load tests and free-decay tests, as well as a suite of tests with wind and wave forcing. A full-scale FAST model of the turbine-TLP system was created for comparison to the results of the tests. Analysis was conducted to validate FASTmore » for modeling the dynamics of this floating system through comparison of FAST simulation results to wave tank measurements. First, a full-scale FAST model of the as-tested scaled configuration of the system was constructed, and this model was then calibrated through comparison to the static load, free-decay, regular wave only, and wind-only tests. Next, the calibrated FAST model was compared to the combined wind and wave tests to validate the coupled hydrodynamic and aerodynamic predictive performance. Limitations of both FAST and the data gathered from the tests are discussed.« less