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Fundamental differences between SPH and grid methods

Agertz, Oscar ; Moore, Ben ; Stadel, Joachim ; Potter, Doug ; Miniati, Francesco ; Read, Justin ; Mayer, Lucio ; Gawryszczak, Artur ; Kravtsov, Andrey ; Nordlund, Åke ; Pearce, Frazer ; Quilis, Vicent ; Rudd, Douglas ; Springel, Volker ; Stone, James ; Tasker, Elizabeth ; Teyssier, Romain ; Wadsley, James ; Walder, Rolf

In: Monthly Notices of the Royal Astronomical Society, 2007, vol. 380, no. 3, p. 963-978

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    Title
    • Fundamental differences between SPH and grid methods
    Author
    • Agertz, Oscar. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
    • Moore, Ben. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
    • Stadel, Joachim. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
    • Potter, Doug. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
    • Miniati, Francesco. Department of Physics, Institute für Astronomie, ETH Zürich, CH-8093 Zürich, Switzerland
    • Read, Justin. Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich, Switzerland
    • Mayer, Lucio. Department of Physics, Institute für Astronomie, ETH Zürich, CH-8093 Zürich, Switzerland
    • Gawryszczak, Artur. Nicolaus Copernicus Astronomical Centre, Bartycka 18, Warsaw PL-00-716, Poland
    • Kravtsov, Andrey. Department of Astronomy & Astrophysics, The University of Chicago, Chicago, IL 60637, USA
    • Nordlund, Åke. Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, DK-2100 København Ø, Denmark
    • Pearce, Frazer. School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD
    • Quilis, Vicent. Departemento de Astronomia y Astrofisica, Universidad de Valencia, 46100 Burjasott, Valencia, Spain
    • Rudd, Douglas. Department of Astronomy & Astrophysics, The University of Chicago, Chicago, IL 60637, USA
    • Springel, Volker. Max-Planck-Institute for Astrophysics, Karl-Schwarzschild-Str. 1, 85740 Garching, Germany
    • Stone, James. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
    • Tasker, Elizabeth. Department of Astronomy, Columbia University, New York, NY 10027, USA
    • Teyssier, Romain. Service d'Astrophysique, CEA/DSM/DAPNIA/SAp, Centre d'Etudes de Saclay, L'orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
    • Wadsley, James. Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L88 4M1, Canada
    • Walder, Rolf. Institute für Astronomie, ETH Zürich, CH-8092 Zürich, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:295254
    Summary
    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