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Title: CASTRO: A NEW COMPRESSIBLE ASTROPHYSICAL SOLVER. I. HYDRODYNAMICS AND SELF-GRAVITY

Abstract

We present a new code, CASTRO, that solves the multicomponent compressible hydrodynamic equations for astrophysical flows including self-gravity, nuclear reactions, and radiation. CASTRO uses an Eulerian grid and incorporates adaptive mesh refinement (AMR). Our approach to AMR uses a nested hierarchy of logically rectangular grids with simultaneous refinement in both space and time. The radiation component of CASTRO will be described in detail in the next paper, Part II, of this series.

Authors:
; ; ; ; ;  [1]; ;  [2];  [3];  [4]
  1. Center for Computational Sciences and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
  2. Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)
  3. Department of Astronomy and Astrophysics, The University of California, Santa Cruz, CA 95064 (United States)
  4. Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)
Publication Date:
OSTI Identifier:
21450909
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 715; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/715/2/1221
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ASTROPHYSICS; EQUATIONS OF STATE; GRAVITATION; HYDRODYNAMICS; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; EQUATIONS; FLUID MECHANICS; MECHANICS; PHYSICS; SYNTHESIS

Citation Formats

Almgren, A. S., Beckner, V. E., Bell, J. B., Day, M. S., Lijewski, M. J., Nonaka, A., Howell, L. H., Singer, M., Joggerst, C. C., and Zingale, M. CASTRO: A NEW COMPRESSIBLE ASTROPHYSICAL SOLVER. I. HYDRODYNAMICS AND SELF-GRAVITY. United States: N. p., 2010. Web. doi:10.1088/0004-637X/715/2/1221.
Almgren, A. S., Beckner, V. E., Bell, J. B., Day, M. S., Lijewski, M. J., Nonaka, A., Howell, L. H., Singer, M., Joggerst, C. C., & Zingale, M. CASTRO: A NEW COMPRESSIBLE ASTROPHYSICAL SOLVER. I. HYDRODYNAMICS AND SELF-GRAVITY. United States. doi:10.1088/0004-637X/715/2/1221.
Almgren, A. S., Beckner, V. E., Bell, J. B., Day, M. S., Lijewski, M. J., Nonaka, A., Howell, L. H., Singer, M., Joggerst, C. C., and Zingale, M. 2010. "CASTRO: A NEW COMPRESSIBLE ASTROPHYSICAL SOLVER. I. HYDRODYNAMICS AND SELF-GRAVITY". United States. doi:10.1088/0004-637X/715/2/1221.
@article{osti_21450909,
title = {CASTRO: A NEW COMPRESSIBLE ASTROPHYSICAL SOLVER. I. HYDRODYNAMICS AND SELF-GRAVITY},
author = {Almgren, A. S. and Beckner, V. E. and Bell, J. B. and Day, M. S. and Lijewski, M. J. and Nonaka, A. and Howell, L. H. and Singer, M. and Joggerst, C. C. and Zingale, M.},
abstractNote = {We present a new code, CASTRO, that solves the multicomponent compressible hydrodynamic equations for astrophysical flows including self-gravity, nuclear reactions, and radiation. CASTRO uses an Eulerian grid and incorporates adaptive mesh refinement (AMR). Our approach to AMR uses a nested hierarchy of logically rectangular grids with simultaneous refinement in both space and time. The radiation component of CASTRO will be described in detail in the next paper, Part II, of this series.},
doi = {10.1088/0004-637X/715/2/1221},
journal = {Astrophysical Journal},
number = 2,
volume = 715,
place = {United States},
year = 2010,
month = 6
}
  • We describe the development of a flux-limited gray radiation solver for the compressible astrophysics code, CASTRO. CASTRO uses an Eulerian grid with block-structured adaptive mesh refinement based on a nested hierarchy of logically rectangular variable-sized grids with simultaneous refinement in both space and time. The gray radiation solver is based on a mixed-frame formulation of radiation hydrodynamics. In our approach, the system is split into two parts, one part that couples the radiation and fluid in a hyperbolic subsystem, and another parabolic part that evolves radiation diffusion and source-sink terms. The hyperbolic subsystem is solved explicitly with a high-order Godunovmore » scheme, whereas the parabolic part is solved implicitly with a first-order backward Euler method.« less
  • We present a formulation for multigroup radiation hydrodynamics that is correct to order O(v/c) using the comoving-frame approach and the flux-limited diffusion approximation. We describe a numerical algorithm for solving the system, implemented in the compressible astrophysics code, CASTRO. CASTRO uses a Eulerian grid with block-structured adaptive mesh refinement based on a nested hierarchy of logically rectangular variable-sized grids with simultaneous refinement in both space and time. In our multigroup radiation solver, the system is split into three parts: one part that couples the radiation and fluid in a hyperbolic subsystem, another part that advects the radiation in frequency space,more » and a parabolic part that evolves radiation diffusion and source-sink terms. The hyperbolic subsystem and the frequency space advection are solved explicitly with high-order Godunov schemes, whereas the parabolic part is solved implicitly with a first-order backward Euler method. Our multigroup radiation solver works for both neutrino and photon radiation.« less
  • Disk self-gravity could play an important role in the dynamic evolution of interaction between disks and embedded protoplanets. We have developed a fast and accurate solver to calculate the disk potential and disk self-gravity forces for disk systems on a uniform polar grid. Our method closely follows the method given by Chan et al., in which a fast Fourier transform in the azimuthal direction is performed and a direct integral approach in the frequency domain in the radial direction is implemented on a uniform polar grid. This method can be very effective for disks with vertical structures that depend onlymore » on the disk radius, achieving the same computational efficiency as for zero-thickness disks. We describe how to parallelize the solver efficiently on distributed parallel computers. We propose a mode-cutoff procedure to reduce the parallel communication cost and achieve nearly linear scalability for a large number of processors. For comparison, we have also developed a particle-based fast tree code to calculate the self-gravity of the disk system with a vertical structure. The numerical results show that our direct integral method is at least two orders of magnitude faster than our optimized tree-code approach.« less
  • Here, an OpenACC directive-based graphics processing unit (GPU) parallel scheme is presented for solving the compressible Navier–Stokes equations on 3D hybrid unstructured grids with a third-order reconstructed discontinuous Galerkin method. The developed scheme requires the minimum code intrusion and algorithm alteration for upgrading a legacy solver with the GPU computing capability at very little extra effort in programming, which leads to a unified and portable code development strategy. A face coloring algorithm is adopted to eliminate the memory contention because of the threading of internal and boundary face integrals. A number of flow problems are presented to verify the implementationmore » of the developed scheme. Timing measurements were obtained by running the resulting GPU code on one Nvidia Tesla K20c GPU card (Nvidia Corporation, Santa Clara, CA, USA) and compared with those obtained by running the equivalent Message Passing Interface (MPI) parallel CPU code on a compute node (consisting of two AMD Opteron 6128 eight-core CPUs (Advanced Micro Devices, Inc., Sunnyvale, CA, USA)). Speedup factors of up to 24× and 1.6× for the GPU code were achieved with respect to one and 16 CPU cores, respectively. The numerical results indicate that this OpenACC-based parallel scheme is an effective and extensible approach to port unstructured high-order CFD solvers to GPU computing.« less