Preprints
https://doi.org/10.5194/wes-2024-40
https://doi.org/10.5194/wes-2024-40
08 Apr 2024
 | 08 Apr 2024
Status: this preprint is currently under review for the journal WES.

Investigating the interactions between wakes and floating wind turbines using FAST.Farm

Lucas Carmo, Jason Jonkman, and Regis Thedin

Abstract. As floating offshore wind progresses to commercial maturity, wake and array effects across a farm of floating offshore wind turbines (FOWTs) will become increasingly important. While wakes of land-based and bottom-fixed offshore wind turbines have been extensively studied, only recently has this topic become relevant for floating turbines. This work presents an investigation on the mutual interaction between the motions of floating wind turbines and wakes using FAST.Farm. While FAST.Farm has been extensively validated across a wide range of conditions, it has never been validated for FOWT applications. Hence, in the first part of this work, we validate FAST.Farm by comparing simulations of a single FOWT against high-fidelity results from large-eddy simulation available in the literature. The validation is based on wake meandering, mean wake deflection, and velocity deficit at different downstream locations. This validation showed that the original, axisymmetric (polar) wake model of FAST.Farm overpredicts the vertical wake deflection induced by shaft tilt and floater pitch, while the new curled wake model is capable of properly capturing the vertical wake deflection. In the second part, we use FAST.Farm to analyze a small three-unit array of FOWTs across a wide range of environmental conditions. The same NREL 5-MW reference wind turbine atop the OC4-DeepCWind semisubmersible is adopted for the three FOWTs and for the validation against high-fidelity simulations. To assess the impact of compliance of the floating substructure, we compare the power production, tower-base moments, and blade-root moments obtained for the floating turbines with the results obtained in a fixed-bottom configuration. In a nutshell, the main differences introduced by the compliance of the floating substructure are the motions induced by the waves, the change in the natural frequencies of the tower caused by differences in the boundary condition at its base, and the larger vertical wake deflection due to the mean pitch of the platform. The impact of these differences, as well as other minor effects, are analyzed in detail.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Lucas Carmo, Jason Jonkman, and Regis Thedin

Status: open (until 06 Jun 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on wes-2024-40', Anonymous Referee #1, 02 May 2024 reply
Lucas Carmo, Jason Jonkman, and Regis Thedin
Lucas Carmo, Jason Jonkman, and Regis Thedin

Viewed

Total article views: 363 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
267 84 12 363 9 8
  • HTML: 267
  • PDF: 84
  • XML: 12
  • Total: 363
  • BibTeX: 9
  • EndNote: 8
Views and downloads (calculated since 08 Apr 2024)
Cumulative views and downloads (calculated since 08 Apr 2024)

Viewed (geographical distribution)

Total article views: 353 (including HTML, PDF, and XML) Thereof 353 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 20 May 2024
Download
Short summary
As floating wind turbines progress to arrays with multiple units, it becomes important to understand how the wake of a floating turbine affects the performance of other units in the array. Due to the compliance of the floating substructure, the wake of a floating wind turbine may behave differently from that of a fixed turbine. In this work, we present an investigation on the mutual interaction between the motions of floating wind turbines and wakes.
Altmetrics