A High-Resolution Adaptive Moving Mesh Hydrodynamic Algorithm, The Astrophysical Journal Supplement Series 115

An algorithm for simulating self-gravitating cosmological astrophysical Ñuids is presented. The advan-tages include a large dynamic range, parallelizability, high resolution per grid element, and fast execution speed. The code is based on a Ðnite volume Ñux-conservative total variation diminishing (TVD) scheme for the shock-capturing hydro and an iterative multigrid solver for the gravity. The grid is a time-dependent Ðeld, whose motion is described by a generalized potential Ñow. Approximately constant mass per cell can be obtained, which provides all the advantages of a Lagrangian scheme. The grid deforma-tion combined with appropriate limiting and smoothing schemes guarantees a regular and well-behaved grid geometry, in which nearest neighbor relationships remain constant. The full hydrodynamic Ñuid equations are implemented in the curvilinear moving grid, which allows for arbitrary Ñuid Ñow relative to the grid geometry. This combination retains all the advantages of the grid-based schemes including high speed per Ñuid element and a rapid gravity solver. The current implementation is described, and empirical simulation results are presented. Accurate execution speed calculations are given in terms of Ñoating point operations per time step per grid cell. This code is freely available to the community. Subject headings: hydrodynamics È large-scale structure of universe È methods: numerical 1