Numerical Simulations of Convective Accretion Flows in Three Dimensions

Abstract

Advection-dominated accretion flows (ADAFs) are known to be convectively unstable for low values of the viscosity parameter a. Two-dimensional axisymmetric hydrodynamic simulations of such flows reveal a radial density profile that is significantly flatter than the rho proportional to r(-3/2) expected for a canonical ADAF. The modified density profile is the result of inward transport of angular momentum by axisymmetric convective eddies. We present three-dimensional hydrodynamic simulations of convective ADAFs that are free of the assumption of axisymmetry. We find that the results are qualitatively and quantitatively similar to those obtained with two-dimensional simulations. In particular the convective eddies are nearly axisymmetric and transport angular momentum inward.