Three-equation turbulent convection models in classical variables

Fuente: arXiv
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Main Authors: Kovács, Gábor B., Szabó, Róbert, Nuspl, János
Format: Preprint
Published: 2026
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author Kovács, Gábor B.
Szabó, Róbert
Nuspl, János
author_facet Kovács, Gábor B.
Szabó, Róbert
Nuspl, János
contents Context. Turbulent convection models in nonlinear radial stellar pulsation models rely on an extra equation for turbulent kinetic energy and fail to adequately explain mode-selection problems. Since multidimensional calculations are computationally expensive, it is reasonable to search for generalizations of physically grounded 1D models that approximate multidimensional results with sufficient accuracy, at least in a given parameter range. A natural way of progressing from one-equation models is to use additional nonlocal equations. While these types of models also exist in the literature, they have not been adopted for this type of object. Aims. We aim to adapt the three-equation turbulent convection model from Kuhfuss to radial stellar pulsation modeling. Methods. We use a Reynolds-stress one-point closure approach to derive our extensions alongside the model, while using additional models from the literature to close the anisotropy and dissipation terms. Results. We provide five extensions to the original model. These include an enhanced dissipation correction to the mixing length, a local anisotropy model replacing eddy viscosity, a second-order correction for turbulent ion transport in the atmosphere (alongside opacity effects), and turbulent damping of entropy fluctuations and convective flux.
format Preprint
id arxiv_https___arxiv_org_abs_2601_04931
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Three-equation turbulent convection models in classical variables
Kovács, Gábor B.
Szabó, Róbert
Nuspl, János
Solar and Stellar Astrophysics
Context. Turbulent convection models in nonlinear radial stellar pulsation models rely on an extra equation for turbulent kinetic energy and fail to adequately explain mode-selection problems. Since multidimensional calculations are computationally expensive, it is reasonable to search for generalizations of physically grounded 1D models that approximate multidimensional results with sufficient accuracy, at least in a given parameter range. A natural way of progressing from one-equation models is to use additional nonlocal equations. While these types of models also exist in the literature, they have not been adopted for this type of object. Aims. We aim to adapt the three-equation turbulent convection model from Kuhfuss to radial stellar pulsation modeling. Methods. We use a Reynolds-stress one-point closure approach to derive our extensions alongside the model, while using additional models from the literature to close the anisotropy and dissipation terms. Results. We provide five extensions to the original model. These include an enhanced dissipation correction to the mixing length, a local anisotropy model replacing eddy viscosity, a second-order correction for turbulent ion transport in the atmosphere (alongside opacity effects), and turbulent damping of entropy fluctuations and convective flux.
title Three-equation turbulent convection models in classical variables
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2601.04931