A turbulent closure model for thin accretion disks
Abstract
A turbulent closure model is applied to the equations of evolution of thin, subsonic accretion disks. Within this framework, the relationship between accretion and turbulent viscosity appears naturally. The influence of rotation on the energy transport easier to interpret. The model can be used both for numerical simulations or theoretical investigations. The main parameter of this model is the turbulence characteristic length scale, which depends on the source of the turbulence. We show here an application of such model, in the case where the shear is the main engine of the turbulence. In this case, the properties and radial structure of stationary thin disks can be analytically determined. The turbulent viscosity can be computed exactly. In units of sound velocity and height of the disk (alpha model), it is alpha = 2 x 0.001. The application to disk around young stars is discussed. It is shown that observed features of disks around TTauri could be reproduced by modifying the length scale prescription, to take into account convective motions and selfgravity. Turbulent viscosity in this case would be alpha about 6 x 0.01.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 December 1992
 Bibcode:
 1992A&A...266..592D
 Keywords:

 Accretion Disks;
 Computational Astrophysics;
 Turbulence Models;
 Astronomical Models;
 Compressibility;
 Energy Transfer;
 Evolution (Development);
 Viscosity;
 Astrophysics