Numerical Analysis and Scientific Computing Seminar

Low Mach Number Models in Computational Astrophysics

Speaker: John Bell, Lawrence Berkeley National Laboratory

Location: Warren Weaver Hall 1302

Date: Oct. 29, 2010, 10 a.m.

Synopsis:

A number of problems in astrophysics are characterized by low Mach number flows. Examples include the convection phase in a white dwarf prior to ignition of a Type Ia supernova, X-ray bursts and convection in massive stars. Low Mach number models analytically remove acoustic wave propagation while retaining compressibility eff ects resulting from nuclear reactions and ambi- ent strati fication. This enables time steps controlled by advective time scales, resulting in signifi cant reduction in computational costs. We will discuss the derivation and basic discretization methodol- ogy for low Mach number models for astrophysical applications and present computational results illustrating application of the methodology, focusing on the convection leading up to ignition in a Type Ia supernova.