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

Cheung, Lawrence Chih-Hui [Sandia National Lab. (SNL-CA), Livermore, CA (United States)] (ORCID:0000000276974739); Yalla, Gopal Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000282061506); Mohan, Prakash [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000338895957); Hsieh, Alan Sean Ker [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0009000528981693); Brown, Kenneth Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000349940047); deVelder, Nathaniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000329169793); Houck, Daniel Russell [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000237007543); Henry de Frahan, Marc T. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000177421565); Day, Marc [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000217113963); Sprague, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000305190379)

doi:10.5194/wes-10-1403-2025

DOE OSTI · 2999188

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

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Abstract

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.

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Cheung, Lawrence Chih-Hui [Sandia National Lab. (SNL-CA), Livermore, CA (United States)] (ORCID:0000000276974739), Yalla, Gopal Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000282061506), Mohan, Prakash [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000338895957), Hsieh, Alan Sean Ker [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0009000528981693), Brown, Kenneth Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000349940047), deVelder, Nathaniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000329169793), Houck, Daniel Russell [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)] (ORCID:0000000237007543), Henry de Frahan, Marc T. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000177421565), Day, Marc [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000217113963), Sprague, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000305190379). 2025-07-18. Modeling the effects of active wake mixing on wake behavior through large-scale coherent structures. https://doi.org/10.5194/wes-10-1403-2025

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