Efficient turbulent compressible convection in the deep stellar atmosphere |
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| Authors: | Chun-Lin Tian Li-Cai Deng Kwing-Lam Chan Da-Run Xiong |
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| Institution: | [1]National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China [3]Department of Mathematics, Hong Kong University of Science and Technology, Hong Kong, China [4]Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China |
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| Abstract: | We report on 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 cμ = 0.25 and an amplitude of artificial viscosity in the gas-kinetic BGK scheme C2 = 0 are appropriate for the current study. We also calculated the density-weighted auto-and cross-correlation functions in Xiong's turbulent stellar convection theory based on which the gradient type of models of the non-local transport and the anisotropy of the turbulence were preliminarily studied. No universal relations or con-stant parameters were found for these models. |
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| Keywords: | convection-hydrodynamic-turbulence-method: numerical-stars:atmosphere |
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