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A comparison of cosmological hydrodynamic codesWe present a detailed comparison of the simulation results of various hydrodynamic codes. Starting with identical initial conditions based on the cold dark matter scenario for the growth of structure, with parameters h = 0.5 Omega = Omega(sub b) = 1, and sigma(sub 8) = 1, we integrate from redshift z = 20 to z = O to determine the physical state within a representative volume of size L(exp 3) where L = 64 h(exp -1) Mpc. Five indenpendent codes are compared: three of them Eulerian mesh-based and two variants of the smooth particle hydrodynamics 'SPH' Lagrangian approach. The Eulerian codes were run at N(exp 3) = (32(exp 3), 64(exp 3), 128(exp 3), and 256(exp 3)) cells, the SPH codes at N(exp 3) = 32(exp 3) and 64(exp 3) particles. Results were then rebinned to a 16(exp 3) grid with the exception that the rebinned data should converge, by all techniques, to a common and correct result as N approaches infinity. We find that global averages of various physical quantities do, as expected, tend to converge in the rebinned model, but that uncertainites in even primitive quantities such as (T), (rho(exp 2))(exp 1/2) persists at the 3%-17% level achieve comparable and satisfactory accuracy for comparable computer time in their treatment of the high-density, high-temeprature regions as measured in the rebinned data; the variance among the five codes (at highest resolution) for the mean temperature (as weighted by rho(exp 2) is only 4.5%. Examined at high resolution we suspect that the density resolution is better in the SPH codes and the thermal accuracy in low-density regions better in the Eulerian codes. In the low-density, low-temperature regions the SPH codes have poor accuracy due to statiscal effects, and the Jameson code gives the temperatures which are too high, due to overuse of artificial viscosity in these high Mach number regions. Overall the comparison allows us to better estimate errors; it points to ways of improving this current generation ofhydrodynamic codes and of suiting their use to problems which exploit their best individual features.
Document ID
19950049365
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kang, Hyesung
(Princeton Univ. Princeton, NJ, United States)
Ostriker, Jeremiah P.
(Princeton Univ. Princeton, NJ, United States)
Cen, Renyue
(Princeton Univ. Princeton, NJ, United States)
Ryu, Dongsu
(Princeton Univ. Princeton, NJ, United States)
Hernquist, Lars
(Univ. of California, Santa Cruz, CA United States)
Evrard, August E.
(niv. of Michigan, Ann Arbor, MI United States)
Bryan, Greg L.
(National Center for Supercomputing Applications, Urbana, IL United States)
Norman, Michael L.
(National Center for Supercomputing Applications, Urbana, IL United States)
Date Acquired
August 16, 2013
Publication Date
July 20, 1994
Publication Information
Publication: The Astrophysical Journal, Part 1
Volume: 430
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A80964
Funding Number(s)
CONTRACT_GRANT: NAGW-2448
CONTRACT_GRANT: NSF ASC-93-18185
CONTRACT_GRANT: NAGW-3152
CONTRACT_GRANT: NAGW-2422
CONTRACT_GRANT: NSF AST-91-08193
CONTRACT_GRANT: NAGW-2367
Distribution Limits
Public
Copyright
Other

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