Fundamental differences between SPH and grid methods
Abstract
We have carried out a hydrodynamical code comparison study of 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 the SPH smoothing kernel over which information is not transferred.
Cite
@article{arxiv.astro-ph/0610051,
title = {Fundamental differences between SPH and grid methods},
author = {Oscar Agertz and Ben Moore and Joachim Stadel and Doug Potter and Francesco Miniati and Justin Read and Lucio Mayer and Artur Gawryszczak and Andrey Kravtsov and Joe Monaghan and Ake Nordlund and Frazer Pearce and Vincent Quilis and Douglas Rudd and Volker Springel and James Stone and Elizabeth Tasker and Romain Teyssier and James Wadsley and Rolf Walder},
journal= {arXiv preprint arXiv:astro-ph/0610051},
year = {2009}
}
Comments
15 pages, 13 figures, to be submitted to MNRAS. For high-resolution figures, please see http://www-theorie.physik.unizh.ch/~agertz/