Modeling the effects of active wake mixing on wake behavior through large-scale coherent structures

<p>The use of active wake mixing (AWM) to mitigate downstream turbine wakes has created new opportunities for reducing power losses in wind farms. However, many current analytical or semi-empirical wake models do not capture the flow instabilities that are excited through the blade pitch actu...

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Bibliographic Details
Main Authors: L. Cheung, G. Yalla, P. Mohan, A. Hsieh, K. Brown, N. deVelder, D. Houck, M. T. Henry de Frahan, M. Day, M. Sprague
Format: Article
Language:English
Published: Copernicus Publications 2025-07-01
Series:Wind Energy Science
Online Access:https://wes.copernicus.org/articles/10/1403/2025/wes-10-1403-2025.pdf
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Summary:<p>The use of active wake mixing (AWM) to mitigate downstream turbine wakes has created new opportunities for reducing power losses in wind farms. However, many current analytical or semi-empirical wake models do not capture the flow instabilities that are excited through the blade pitch actuation. In this work, we develop a framework, which accounts for the impacts of the large-scale coherent structures and turbulence on the mean flow, for modeling AWM. The framework uses a triple-decomposition approach for the unsteady flow field and models the mean flow and fine-scale turbulence with a parabolized Reynolds-averaged Navier–Stokes (RANS) system. The wave components are modeled using a simplified spatial linear stability formulation that captures the growth and evolution of the coherent structures. Comparisons with high-fidelity large eddy simulations (LESs) of the turbine wakes showed that this framework was able to capture the additional wake mixing and faster wake recovery in the far-wake regions for both the pulse and helix AWM strategies with minimal computational expense. In the near-wake region, some differences are observed in both the RANS velocity profiles and initial growth of the large-scale structures, which may be due to some simplifying assumptions used in the model.</p>
ISSN:2366-7443
2366-7451