Evolution of Eddy Viscosity in the Wake of a Wind Turbine

Research output: Contribution to journalArticle

Abstract

The eddy viscosity hypothesis is a popular method in wind turbine wake modeling for estimating turbulent stresses. We document the downstream evolution of eddy viscosity in the wake of a wind turbine from experimental and large eddy simulation data. Wake eddy viscosity is isolated from its surroundings by subtracting the inflow profile and the driving forces are identified in each wake region. Eddy viscosity varies in response to changes in turbine geometry and nacelle misalignment with larger turbines generating stronger velocity gradients and shear stresses. We propose a model for eddy viscosity based on a Rayleigh distribution curve. Model parameters are obtained from scaling the eddy viscosity hypothesis and demonstrate satisfactory agreement with the reference data. The model is implemented in the curled wake formulation in the FLOw Redirection and Induction in Steady State (FLORIS) framework and assessed through comparisons to the previous formulation. Our approach produced more accurate flow field estimates with lower total error for the majority of cases.
Original languageAmerican English
Number of pages22
JournalWind Energy Science Discussions
DOIs
StatePublished - 2022

Bibliographical note

See NREL/JA-5000-87589 for final paper as published in Wind Energy Science

NREL Publication Number

  • NREL/JA-5000-83639

Keywords

  • curled wake model
  • eddy viscosity
  • wind turbine wake

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