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Main Authors: Baungaard, Mads, Nishino, Takafumi, Kirby, Andrew
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.10126
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author Baungaard, Mads
Nishino, Takafumi
Kirby, Andrew
author_facet Baungaard, Mads
Nishino, Takafumi
Kirby, Andrew
contents A key parameter in the two-scale momentum theory of wind farm flows is the momentum availability, which quantifies the supply of momentum to a wind farm from various different momentum transport mechanisms (advection, pressure gradient, Coriolis, turbulence and unsteadiness). In this study, the contribution of each of these mechanisms to the momentum availability is evaluated directly from large-eddy simulation (LES) data in order to validate an analytic momentum availability model (Kirby, Dunstan, & Nishino, J. Fluid Mech., vol. 976, 2023, A24). Application of the model to six wind farm cases, three with different atmospheric boundary-layer (ABL) heights and three with different turbine layouts, shows that the full model performs well across all cases, but that its linearized version increasingly overpredicts the momentum availability for increasing ABL heights. It is found that the overprediction is related to the ABL Rossby number, and based on this observation, we propose an extension of the original linear model, which improves its accuracy for the considered cases and makes it more generally applicable, in particular to cases with tall ABL heights or strong Coriolis forcing.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10126
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Validation and extension of an analytic momentum availability model for the two-scale momentum theory of wind farm flows
Baungaard, Mads
Nishino, Takafumi
Kirby, Andrew
Fluid Dynamics
A key parameter in the two-scale momentum theory of wind farm flows is the momentum availability, which quantifies the supply of momentum to a wind farm from various different momentum transport mechanisms (advection, pressure gradient, Coriolis, turbulence and unsteadiness). In this study, the contribution of each of these mechanisms to the momentum availability is evaluated directly from large-eddy simulation (LES) data in order to validate an analytic momentum availability model (Kirby, Dunstan, & Nishino, J. Fluid Mech., vol. 976, 2023, A24). Application of the model to six wind farm cases, three with different atmospheric boundary-layer (ABL) heights and three with different turbine layouts, shows that the full model performs well across all cases, but that its linearized version increasingly overpredicts the momentum availability for increasing ABL heights. It is found that the overprediction is related to the ABL Rossby number, and based on this observation, we propose an extension of the original linear model, which improves its accuracy for the considered cases and makes it more generally applicable, in particular to cases with tall ABL heights or strong Coriolis forcing.
title Validation and extension of an analytic momentum availability model for the two-scale momentum theory of wind farm flows
topic Fluid Dynamics
url https://arxiv.org/abs/2602.10126