by James M. Stone, revised 2/21/97

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Abstract: A two-dimensional radiation hydrodynamics (RHD) algorithm based on the flux limited diffusion method is described which, when combined with the ZEUS-2D astrophysical fluid dynamics code described by Norman and Stone, can be used for RHD simulations. The algorithm assumes the radiation is in local thermodynamic equilibrium (LTE) with the material component of the fluid, and currently only frequency independent (gray) opacities are implemented. Extending the algorithm to relax either of these assumptions is straightforward but costly. Comparison of dynamical simulations computed with flux limited diffusion algorithms as implemented here and more general full transport methods is encouragerd.