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A new two-columns description for convective transport in stars

Published online by Cambridge University Press:  01 April 2008

Alexander Stökl
Alexander Stökl*
Affiliation:
CRAL, Université de Lyon, CNRS (UMR5574), École Normale Supérieure de Lyon, F-69007 Lyon, France email: [email protected]
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Abstract

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Assuming that the largest convective patterns generate the majority of convective transport, we devise a numerical scheme simplifying the convective velocity field using two parallel radial columns to represent up- and downstream flows. Horizontal exchange is described by fluid flow and radiation over the interface between those two columns. The main parameters of this convective description have a straightforward geometrical meaning, namely the diameter of the columns (representing the size of the convective cells) and the ratio of cross section between up- and downdrafts. For this geometrical setup, the equations of radiation hydrodynamics are solved time-dependently using an implicit scheme which has the advantage of being devoid of any time step limits. In order to demonstrate our approach, we present comparisons with detailed 2D hydrodynamics computations for the example of convection zones in Cepheids.

Keywords

hydrodynamics — Cepheids — convection — methods: numerical
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 4 , Symposium S252: The Art of Modeling Stars in the 21st Century , April 2008 , pp. 89 - 95
Copyright
Copyright © International Astronomical Union 2008

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