A Note on Hydrodynamic Viscosity and Selfgravitation in Accretion Disks
  We propose a generalized accretion disk viscosity prescription based on hydrodynamically driven turbulence at the critical effective Reynolds number. This approach is consistent with recent re-analysis by Richard & Zahn (1999) of experimental results on turbulent Couette-Taylor flows. This new $\beta$-viscosity formulation is applied to both selfgravitating and non-selfgravitating disks and is shown to yield the standard $\alpha$-disk prescription in the case of shock dissipation limited, non-selfgravitating disks. A specific case of fully selfgravitating $\beta$-disks is analyzed. We suggest that such disks may explain the observed spectra of protoplanetary disks and yield a natural explanation for the radial motions inferred from the observed metallicity gradients in disk galaxies. The $\beta$-mechanism may also account for the rapid mass transport required to power ultra luminous infrared galaxies. 
Wolfgang J. Duschl (1,3), Peter A. Strittmatter (2,3), and Peter L.   Biermann (3) ((1) Institut f"ur Theoretische Astrophys...