A Hybrid Cosmological Hydrodynamic/N-body Code Based on a Weighted Essentially Non-Oscillatory Scheme

We present a newly developed cosmological hydrodynamics code based on weighted essentially non-oscillatory (WENO) schemes for hyperbolic conservation laws and related Hamilton-Jacobi equations. WENO is a higher order accurate finite difference scheme designed for problems with piecewise smooth solutions containing discontinuities, and has been successful in application for problems involving both shocks and complicated smooth solution structures. We couple hydrodynamics based on the WENO scheme with standard Poisson solver particle-mesh (PM) algorithm for evolving the self-gravitating system. The third order total variation diminishing (TVD) Runge-Kutta scheme has been used for time-integration of the system. To test the performance of the code, we subject it to a number of typical tests including the Sod shock tube in multidimension, the Sedov blast wave and formation of the Zeldovich pancake. These tests validate the WENO hydrodynamics with fast convergence rate and high accuracy. Also, we evolve a low density flat cosmological model (ΛCDM) to explore validity of the code in practical simulations. Subject headings: cosmology: theory large-scale structure of the universe Purple Mountain Observatory, Nanjing, 210008, P.R. China. E-mail: [email protected] Center for Astrophysics, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China National Astronomical Observatories, Chinese Academy of Science, Chao-Yang District, Beijing 100012, P.R. China Division of Applied Mathematics, Brown University, Providence, RI 02912, U.S.A. E-mail: [email protected] Department of Mathematics, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China. E-mail: [email protected]