The mixing length parameter alpha
Abstract
The standard mixing length theory, MLT, treats turbulent eddies as if they were isotropic, while the largest eddies that carry most of the flux are highly anisotropic. Recently, an anisotropic MLT was constructed, and the relevant equations derived. It is shown that these new equations can actually be cast in a form that is formally identical to that of the standard isotropic MLT, provided the mixing length parameter, derived from stellar structure calculations, is interpreted as an intermediate, auxiliary function alpha(x), where x, the degree of anisotropy is given as a function of the thermodynamic variables of the problem. The relation between alpha(x) and the physically relevant alpha(l = Hp) is also given. Once the value alpha is deduced, it is found to be a function of the local thermodynamic quantities, as expected.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 January 1990
 Bibcode:
 1990A&A...227..282C
 Keywords:

 Computational Astrophysics;
 Mixing Length Flow Theory;
 Stellar Structure;
 Turbulence Effects;
 Astronomical Models;
 Thermodynamic Properties;
 Astrophysics