A test suite for quantitative comparison of hydrodynamic codes in astrophysics

By Elizabeth J. Tasker, R. Brunino, N. L. Mitchell, D. Michielsen, S. Hopton, Frazer R. Pearce, Greg L. Bryan, Tom Theuns University of Florida, U. Nottingham, U. Durham and 1 more. 2008

139 citations recorded by the source corpus.

We test four commonly used astrophysical simulation codes, enzo, flash, gadget and hydra, using a suite of numerical problems with analytic initial and final states. Situations similar to the conditions of these tests, a Sod shock, a Sedov blast, and both a static and translating King sphere, occur commonly in astrophysics, where the accurate treatment of shocks, sound waves, supernovae explosions and collapsed haloes is a key condition for obtaining reliable validated simulations. We demonstrate that comparable results can be obtained for Lagrangian and Eulerian codes by requiring that approximately one particle exists per grid cell in the region of interest. We conclude that adaptive Eulerian codes, with their ability to place refinements in regions of rapidly changing density, are well suited to problems where physical processes are related to such changes. Lagrangian methods, on the other hand, are well suited to problems where large density contrasts occur and the physics are related to the local density itself rather than the local density gradient.

Subfields: Astronomy and Astrophysics, Computational Mechanics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/60adf401c4065166b23710c8059f6824285c70c4

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Citations in the corpus

Smoothed Particle Hydrodynamics in Astrophysics (2010, background): “There have been a few code comparisons in the literature between SPH and Eulerian hydrodynamics (Frenk et al., 1999; O’Shea et al., 2005; Tasker et al., 2008), but very few formal studies of the accuracy of SPH have been carried out.”
E pur si muove: Galilean-invariant cosmological hydrodynamical simulations on a moving mesh (2009, background): “An issue of great concern is that these methods sometimes yield conflicting results even for basic calculations that only consider non-radiative hydrodynamics (e.g. Agertz et al., 2007; Tasker et al., 2008; Mitchell et al., 2009).”
Shock waves in Eulerian cosmological simulations: main properties and acceleration of cosmic rays (2008, background): “Although the shock discontinuity in ENZO is found to be well reconstructed within two–four cells (e.g. Tasker et al. 2008), the risk that comes from the application of procedures based on cell-to-cell jumps (or jumps between a few cells) is to underestimate the value of the Mach number of the shock.”
Gasoline2: a modern smoothed particle hydrodynamics code (2017, background): “…codes generally agree well in simulations that involve supersonic flow (e.g. comparison projects by Kitsionas et al. 2009; Price & Federrath 2010; Bauer & Springel 2012), highMach number shocks (Tasker et al. 2008; Sijacki et al. 2012) and gravitational structure formation (O’Shea et al. 2005).”
Moving mesh cosmology: numerical techniques and global statistics (2011, background): “Because the truncation error of Eulerian codes depends on the fluid velocity relative to the grid, the results can thus be sensitive to the presence of bulk velocities (see also Tasker et al. 2008; Wadsley, Veeravalli & Couchman 2008).”
HYDRODYNAMICAL SIMULATIONS TO DETERMINE THE FEEDING RATE OF BLACK HOLES BY THE TIDAL DISRUPTION OF STARS: THE IMPORTANCE OF THE IMPACT PARAMETER AND STELLAR STRUCTURE (2012, background): “The solution to the Riemann problem is sensitive to the velocity of the frame in which the problem is solved, and poor solutions can be returned in regions where the velocity of the frame is many times larger than the sound speed (Tasker et al. 2008; Robertson et al. 2010; Springel 2010).”
STAR FORMATION IN DISK GALAXIES. I. FORMATION AND EVOLUTION OF GIANT MOLECULAR CLOUDS VIA GRAVITATIONAL INSTABILITY AND CLOUD COLLISIONS (2008, background): “Particle-based techniques also struggle to resolve fluid instabilities (Tasker et al. 2008) and can suffer from over-mixing problems unless specific algorithmic steps are taken.”
Implementation of feedback in smoothed particle hydrodynamics: towards concordance of methods (2012, methodology): “We recall that Sedov’s problem with thermal energy input has already been numerically solved with SPH (e.g. Springel & Hernquist 2002; Tasker et al. 2008), reaching the desired integration accuracy by limiting the particle maximum time-step or evolving the system on small, constant time-steps.”
Turbulent Motions and Shocks Waves in Galaxy Clusters simulated with AMR (2009, unknown): “…in resolving the smallest structures within galaxy clusters, they may suffer of serious limitations in modeling fluid instabilities, mostly because of the effects played by the artificial viscosity employed to solve hydro equations (e.g. Agertz et al.2007; Tasker et al.2008; Mitchell et al.2009).”
The Aquila comparison project: the effects of feedback and numerical methods on simulations of galaxy formation (2011, background): “As a result, even for some simple non-radiative problems, Lagrangian and Eulerian codes do not converge to the same solution (e.g. Okamoto et al. 2003; Agertz et al. 2007; Tasker et al. 2008; Mitchell et al. 2009).”
ENZO: AN ADAPTIVE MESH REFINEMENT CODE FOR ASTROPHYSICS (2013, background): “The three-dimensional results from this test, both for Enzo and three other leading astrophysics codes, can be found in Tasker et al. (2008).”
Phantom: A Smoothed Particle Hydrodynamics and Magnetohydrodynamics Code for Astrophysics (2017, methodology): “For previous uses of this test with SPH, see e.g. Springel & Hernquist (2002); Rosswog & Price (2007) and for a comparison between SPH and mesh codes on this test see Tasker et al. (2008).”
X-ray coronae in simulations of disc galaxy formation (2010, methodology): “SPH has been shown to reproduce the analytic solutions of simple problems such as shock tubes, spherical collapse, and Sedov blasts (e.g. Springel 2005; Tasker et al. 2008).”
MODELING COLLAPSE AND ACCRETION IN TURBULENT GAS CLOUDS: IMPLEMENTATION AND COMPARISON OF SINK PARTICLES IN AMR AND SPH (2010, unknown): “…the ambipolar diffusion module, and with either the multigrid or the tree gravity solver. flash has been extensively tested against laboratory experiments (Calder et al. 2002) and other codes (Dimonte et al. 2004; Heitmann et al. 2005; Agertz et al. 2007; Tasker et al. 2008; Kitsionas et al. 2009).”
Chaotic cold accretion on to black holes (2013, result): “As shown by comparison studies (e.g. Agertz et al. 2007; Tasker et al. 2008; Mitchell et al. 2009; Bauer & Springel 2012) fluid instabilities, discontinuities, mixing and turbulence are poorly resolved or even suppressed by SPH techniques.”
ramses-rt: radiation hydrodynamics in the cosmological context (2013, methodology): “The drawbacks and advantages of each method have been thoroughly explored (e.g. Agertz et al. 2007; Tasker et al. 2008; Wadsley, Veeravalli & Couchman 2008) and we now believe that both code types agree more or less on the final result if they are used carefully with recently developed fixes and…”