Fundamental differences between SPH and grid methods

By O. Agertz, B. Moore, Joachim Stadel, D. Potter, Francesco Miniati, Justin I. Read, Lucio Mayer, A. Gawryszczak, Andrey V. Kravtsov, Joseph J Monaghan and 10 more. 2006

552 citations recorded by the source corpus.

We have carried out a comparison study of hydrodynamical codes by investigating their performance in modelling interacting multiphase fluids. The two commonly used techniques of grid and smoothed particle hydrodynamics (SPH) show striking differences in their ability to model processes that are fundamentally important across many areas of astrophysics. Whilst Eulerian grid based methods are able to resolve and treat important dynamical instabilities, such as Kelvin-Helmholtz or Rayleigh-Taylor, these processes are poorly or not at all resolved by existing SPH techniques. We show that the reason for this is that SPH, at least in its standard implementation, introduces spurious pressure forces on particles in regions where there are steep density gradients. This results in a boundary gap of the size of an SPH smoothing kernel radius over which interactions are severely damped.

Subfields: Computational Mechanics, Computer Graphics and Computer-Aided Design

View Paper: https://www.semanticscholar.org/paper/3773770a529ac59899ad425ec4207c1cf4fd9aff

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Citations in the corpus

Cosmological simulations of the formation of the stellar haloes around disc galaxies (2011, background): “For idealised test cases it has been shown that the SPH formalism can inhibit the development of fluid instabilities (e.g., Agertz et al. 2007; Mitchell et al. 2009), which could potentially disrupt the clouds/filaments.”
The Causes of Halo Shape Changes Induced by Cooling Baryons: Disks versus Substructures (2007, background): “Agertz et al. (2007) demonstrate that the evolution of gas blobs in smoothed particle hydrodynamics (SPH) simulations is different from that found in Eulerian gas codes.”
Theoretical Challenges in Galaxy Formation (2016, background): “…has to be modified for typical astrophysical conditions including shocks, shear and large temperature gradients and it has become clear that some standard implementations have serious difficulties to properly model fluid mixing and sub-sonic turbulence (Agertz et al. 2007, Springel 2010b).”
A DENSITY-INDEPENDENT FORMULATION OF SMOOTHED PARTICLE HYDRODYNAMICS (2012, methodology): “Finally, we show the results of the blob tests which was first proposed by Agertz et al. (2007).”
Intracluster stars in simulations with active galactic nucleus feedback (2010, background): “For example, SPH simulations are known to poorly resolve fluid instabilities (e.g. Agertz et al. 2007) that could act to disrupt such gas clouds after they are stripped from an infalling halo.”
Physical Models of Galaxy Formation in a Cosmological Framework (2014, background): “…noted that a side-effect of EC-SPH is to create an artificial pressure between cold and hot phases, resulting in a surface tension that causes for example cold clumps moving through a hot medium to be significantly more resistant to disruption than they are in grid-based codes (Agertz et al. 2007).”
Compaction and quenching of high-z galaxies in cosmological simulations: blue and red nuggets (2014, methodology): “AMR codes more accurately trace some of the high-resolution hydrodynamical processes involved in galaxy formation than SPH codes that use the traditional density formulation (e.g. Agertz et al. 2007; Scannapieco et al. 2012; Bauer & Springel 2012).”
Modelling discontinuities and Kelvin-Helmholtz instabilities in SPH (2007, methodology): “Finally, we consider the problem of Kelvin-Helmholtz instabilities across a density jump, on which recent problems have been highlighted by Agertz et al. (2007). We set up the problem in two spatial dimensions, using equal mass particles in a periodic box in the domain −0.”
Shocking results without shocks: Subsonic turbulence in smoothed particle hydrodynamics and moving-mesh simulations (2011, background): “However, an examination of this question is particularly timely because serious differences between Eulerian mesh-codes and SPH have been reported in a number of recent papers (e.g. Agertz et al. 2007).”
MUFASA: Galaxy Formation Simulations With Meshless Hydrodynamics (2016, methodology): “A reformulation of the SPH equations to explicitly conserve entropy provides some advantages (Springel & Hernquist 2002; Springel 2005), but still resulted in numerical surface tension that e.g. strongly supresses KelvinHemholtz instabilities (Agertz et al. 2007).”
Cold gas stripping in satellite galaxies: from pairs to clusters (2016, unknown): “…(2013) employ entropy-conserving smoothed particle hydrodynamics (SPH; Springel 2005) that has been shown to handle surface instabilities such as those that occur during gas stripping poorly compared to more recent hydrodynamics methods (see Agertz et al. 2007; Hopkins 2015; Schaller et al. 2015).”
Galaxies in a simulated ΛCDM Universe – I. Cold mode and hot cores (2008, background): “Finally, SPH codes have difficulty following surface instabilities that should develop when cold dense clumps move through a hot dilute medium (Agertz et al. 2007), so clouds that should be destroyed by instabilities or by conduction (which is not included in our simulations) may artificially…”
Gravitational quenching in massive galaxies and clusters by clumpy accretion (2007, background): “While there have been preliminary attempts to resolve small clumps using SPH simulations (Kaufmann et al. 2006), a proper treatment of the hydrodynamical instabilities associated with the clumps will probably require the use of an adaptive Euleriangrid simulation technique (Agertz et al. 2007).”