Reynolds number dependence of turbulence statistics in the wake of wind turbines

Leonardo P. Chamorro, R. E A Arndt, Fotis Sotiropoulos

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

A wind tunnel experiment has been performed to quantify the Reynolds number dependence of turbulence statistics in the wake of a model wind turbine. A wind turbine was placed in a boundary layer flow developed over a smooth surface under thermally neutral conditions. Experiments considered Reynolds numbers on the basis of the turbine rotor diameter and the velocity at hub height, ranging from Re = 1.66 × 10 4 to 1.73 × 10 5. Results suggest that main flow statistics (mean velocity, turbulence intensity, kinematic shear stress and velocity skewness) become independent of Reynolds number starting from Re ≈ 9.3 × 10 4. In general, stronger Reynolds number dependence was observed in the near wake region where the flow is strongly affected by the aerodynamics of the wind turbine blades. In contrast, in the far wake region, where the boundary layer flow starts to modulate the dynamics of the wake, main statistics showed weak Reynolds dependence. These results will allow us to extrapolate wind tunnel and computational fluid dynamic simulations, which often are conducted at lower Reynolds numbers, to full-scale conditions. In particular, these findings motivates us to improve existing parameterizations for wind turbine wakes (e.g. velocity deficit, wake expansion, turbulence intensity) under neutral conditions and the predictive capabilities of atmospheric large eddy simulation models.

Original languageEnglish (US)
Pages (from-to)733-742
Number of pages10
JournalWind Energy
Volume15
Issue number5
DOIs
StatePublished - Jul 1 2012

Keywords

  • Reynolds number
  • atmospheric boundary layer
  • turbulence
  • wind tunnel experiment
  • wind turbine wake

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