On the Characteristics of the Wake of a Wind Turbine Undergoing Large Motions Caused by a Floating Structure: An Insight Based on Experiments and Multi-Fidelity Simulations from the OC6 Phase III Project

Stefano Cioni, Francesco Papi, Leonardo Pagamonci, Alessandro Bianchini, Nestor Ramos-Garcia, Georg Pirrung, Remi Corniglion, Anais Lovera, Josean Galvan, Ronan Boisard, Alessandro Fontanella, Paolo Schito, Alberto Zasso, Marco Belloli, Andrea Sanvito, Giacomo Persico, Lijun Zhang, Ye Li, Yarong Zhou, Simone ManciniKoen Boorsma, Ricardo Amaral, Axelle Vire, Christian Schulz, Stefan Netzband, Rodrigo Soto-Valle, David Marten, Raquel Martin-San-Roman, Pau Trubat, Climent Molins, Roger Bergua, Emmanuel Branlard, Jason Jonkman, Amy Robertson

Research output: Contribution to journalArticlepeer-review

5 Scopus Citations

Abstract

This study reports the results of the second round of analyses of the Offshore Code Comparison, Collaboration, Continued, with Correlation and unCertainty (OC6) project Phase III. While the first round investigated rotor aerodynamic loading, here, focus is given to the wake behavior of a floating wind turbine under large motion. Wind tunnel experimental data from the UNsteady Aerodynamics for FLOating Wind (UNAFLOW) project are compared with the results of simulations provided by participants with methods and codes of different levels of fidelity. The effect of platform motion on both the near and the far wake is investigated. More specifically, the behavior of tip vortices in the near wake is evaluated through multiple metrics, such as streamwise position, core radius, convection velocity, and circulation. Additionally, the onset of velocity oscillations in the far wake is analyzed because this can have a negative effect on stability and loading of downstream rotors. Results in the near wake for unsteady cases confirm that simulations and experiments tend to diverge from the expected linearized quasi-steady behavior when the rotor reduced frequency increases over 0.5. Additionally, differences across the simulations become significant, suggesting that further efforts are required to tune the currently available methodologies in order to correctly evaluate the aerodynamic response of a floating wind turbine in unsteady conditions. Regarding the far wake, it is seen that, in some conditions, numerical methods overpredict the impact of platform motion on the velocity fluctuations. Moreover, results suggest that the effect of platform motion on the far wake, differently from original expectations about a faster wake recovery in a floating wind turbine, seems to be limited or even oriented to the generation of a wake less prone to dissipation.
Original languageAmerican English
Pages (from-to)1659-1691
Number of pages33
JournalWind Energy Science
Volume8
Issue number11
DOIs
StatePublished - 2023

Bibliographical note

See NREL/JA-5000-85368 for article as published in Wind Energy Science Discussions

NREL Publication Number

  • NREL/JA-5000-88496

Keywords

  • aerodynamics
  • floating wind turbines
  • IEA Wind Task 30
  • OC6
  • wind turbine wake

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