Volker Springel
Max-Planck-Institut für Astrophysik (Garching, Allemagne)
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
|
| « Moving mesh hydrodynamics: A new medicine to cure long-standing maladies in cosmological simulations » |
|
Volker Springel |
| Hydrodynamic cosmological simulations are a powerful tool to study structure formation in the Universe. At present, they usually either employ the Lagrangian smoothed particle hydrodynamics (SPH) technique, or Eulerian hydrodynamics on a cartesian mesh with adaptive mesh refinement (AMR). However, both of these methods have a number of disadvantages that can negatively impact their accuracy in certain situations. In my talk I describe a novel scheme to calculate hydrodynamical flows which largely eliminates these weaknesses. It is based on a moving unstructured mesh that is defined as the Voronoi tessellation of a set of discrete points. I show that the new method is fully Galilei-invariant, unlike ordinary Eulerian codes, but at the same time offers comparable accuracy for treating shocks, and even an improved treatment of contact discontinuities. The new scheme adjusts its spatial resolution to the local clustering of the flow automatically and continuously, and hence retains a principle advantage of SPH for simulations of cosmological structure growth. Using illustrative example, I will also discuss issues of parallelization, adaptive time integration and the treatment of self-gravity. |
|
vendredi 5 décembre 2008 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |