  We compare the results of numerical simulations of thin and quasi-spherical
(thick) accretion flows with existing analytical solutions. We use a Lagrangian
code based on the Smooth Particle Hydrodynamics (SPH) scheme and an Eulerian
finite difference code based on the Total Variation Diminishing (TVD) scheme.
In one-dimensional thin flows, the results of the simulations, with or without
shocks, agree very well with each other and with analytical solutions. In
two-dimensional thick flows, the general features, namely the locations and
strengths of centrifugal and turbulent pressure supported shocks, centrifugal
barriers, and the funnel walls which are expected from analytical models, agree
very well, though the details vary. Generally speaking, the locations of the
shocks may be better obtained by SPH since the angular momentum is strictly
preserved in SPH, but the shocks themselves are better resolved by TVD. The
agreement of these code test results with analytical solutions provides us with
confidence to apply these codes to more complex problems which we will discuss
elsewhere.
