Distinct turbulent regions in the wake of a wind turbine and their inflow-dependent locations: The creation of a wake map

Ingrid Neunaber*, Michael Hölling, Richard J.A.M. Stevens, Gerard Schepers, Joachim Peinke

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
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Abstract

Wind turbines are usually clustered in wind farms which causes the downstream turbines to operate in the turbulent wakes of upstream turbines. As turbulence is directly related to increased fatigue loads, knowledge of the turbulence in the wake and its evolution are important. Therefore, the main objective of this study is a comprehensive exploration of the turbulence evolution in the wind turbine's wake to identify characteristic turbulence regions. For this, we present an experimental study of three model wind turbine wake scenarios that were scanned with hot-wire anemometry with a very high downstream resolution. The model wind turbine was exposed to three inflows: laminar inflow as a reference case, a central wind turbine wake, and half of the wake of an upstream turbine. A detailed turbulence analysis reveals four downstream turbulence regions by means of the mean velocity, variance, turbulence intensity, energy spectra, integral and Taylor length scales, and the Castaing parameter that indicates the intermittency, or gustiness, of turbulence. In addition, a wake core with features of homogeneous isotropic turbulence and a ring of high intermittency surrounding the wake can be identified. The results are important for turbulence modeling in wakes and optimization of wind farm wake control.

Original languageEnglish
Article number5392
JournalEnergies
Volume13
Issue number20
DOIs
Publication statusPublished - 15 Oct 2020

Keywords

  • Homogeneous isotropic turbulence
  • Turbulence
  • Turbulence decay
  • Wake map
  • Wind turbine wake

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