The Construction of a Conservative Radiation Hydrodynamics Algorithm in Two-Dimensional Spherical Geometry

This paper presents the construction of a conservative radiation hydrodynamics algorithm in two-dimensional (2D) spherical geometry. First, we discretize the radiation transport equation (RTE) in that geometry. The discretization preserves the conservation of photons by integrating the original RTE in 2D spherical coordinates over both angular and spatial control volumes. Some numerical results are provided to verify the discretization for both optically thin and thick circumstances. Second, we formulate the staggered Lagrangian hydrodynamics in that geometry. The formulation preserves the conservation of mass, momentum, and energy by integrating the original hydrodynamic equations in 2D spherical coordinates over their respective control volumes. The original edge-centered artificial viscosity in 2D cylindrical geometry is also extended to be capable of capturing shock waves in 2D spherical geometry. Several 2D benchmark cases are provided to verify the scheme. The subsequent construction of the conservative radiation hydrodynamics algorithm is accomplished by the combination of the staggered Lagrangian hydrodynamics scheme and the solution of the RTE in 2D spherical geometry. Several 2D problems are calculated to verify our radiation hydrodynamics algorithm at the end.