Stellar turbulent convection - A new model and applications

Journal Article · Fri Mar 01 00:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169815· OSTI ID:5757372

Canuto, V M; Mazzitelli, I ^[1]

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1. NASA, Goddard Institute for Space Studies, NY (USA) CNR, Istituto di Astrofisica Spaziale, Frascati (Italy)

Improvements of the mixing-length theory (MLT) of turbulent convection in stellar atmospheres are developed theoretically. It is pointed out that inaccuracies are introduced into MLT by the approximating assumptions of a single large eddy (rather than many eddies of different sizes) and of incompressibility. In the proposed new model, the full spectrum of turbulent eddies is determined using more recent turbulence models (e.g., the eddy-damped quasi-normal Markovian model of Orszag, 1977), and a new formula for the convective flux is obtained which gives values up to 10 times greater than those of the MLT at high convective efficiencies. The problem of compressibility is addressed by adding one of two new expressions (one with no free parameters) for the mixing length. Numerical results from simulations of a solar-type star and a 0.8-solar-mass globular-cluster star are presented in tables and graphs and discussed in detail; the agreement with observations is found to be better than with the MLT. 65 refs.

• OSTI ID: 5757372
• Journal Information: Astrophysical Journal; (USA), Vol. 370; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
STAR EVOLUTION
STELLAR ATMOSPHERES
NATURAL CONVECTION
ASTROPHYSICS
DATA
ENERGY SPECTRA
MAGNETOHYDRODYNAMICS
MASS
MORPHOLOGY
NUMERICAL SOLUTION
STAR CLUSTERS
STAR MODELS
TURBULENCE
ATMOSPHERES
CONVECTION
ENERGY TRANSFER
FLUID MECHANICS
HEAT TRANSFER
HYDRODYNAMICS
INFORMATION
MASS TRANSFER
MATHEMATICAL MODELS
MECHANICS
SPECTRA
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources