Efficient Turbulent Compressible Convection in the Deep Stellar Atmosphere

This paper reports an application of gas-kinetic BGK scheme to the computation of turbulent compressible convection in the stellar interior. After incorporating the Sub-grid Scale (SGS) turbulence model into the BGK scheme, we tested the effects of numerical parameters on the quantitative relationsh...

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Bibliographic Details
Published in:arXiv.org 2008-07
Main Authors: Chun-Lin, Tian, Li-Cai, Deng, Chan, Kwing-Lam, Da-Run, Xiong
Format: Article
Language:English
Subjects:
Anisotropy
Astronomical models
Atmospheric models
Compressibility
Parameters
Stellar convection
Thermodynamic properties
Turbulence models
Variation
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Summary:This paper reports an application of gas-kinetic BGK scheme to the computation of turbulent compressible convection in the stellar interior. After incorporating the Sub-grid Scale (SGS) turbulence model into the BGK scheme, we tested the effects of numerical parameters on the quantitative relationships among the thermodynamic variables, their fluctuations and correlations in a very deep, initially gravity-stratified stellar atmosphere. Comparison indicates that the thermal properties and dynamic properties are dominated by different aspects of numerical models separately. An adjustable Deardorff constant in the SGS model \(c_\mu=0.25\) and an amplitude of artificial viscosity in the gas-kinetic BGK scheme \(C_2=0\) are appropriate for current study. We also calculated the density-weighted auto- and cross-correlation functions in Xiong's (\cite{xiong77}) turbulent stellar convection theories based on which the gradient type of models of the non-local transport and the anisotropy of the turbulence are preliminarily studied. No universal relations or constant parameters were found for these models.
ISSN:2331-8422
DOI:10.48550/arxiv.0807.2716