On the Evolution of Thermonuclear Flames on Large Scales

Abstract

The thermonuclear explosion of a massive white dwarf in a Type Ia supernova explosion is characterized by vastly disparate spatial and temporal scales. The extreme dynamic range inherent to the problem prevents the use of direct numerical simulation and forces modelers to resort to subgrid models to describe physical processes taking place on unresolved scales. We consider the evolution of a model thermonuclear flame in a constant gravitational field on a periodic domain. The gravitational acceleration is aligned with the overall direction of the flame propagation, making the flame surface subject to the Rayleigh-Taylor instability. The flame evolution is followed through an extended initial transient phase well into the steady-state regime. The properties of the evolution of flame surface are examined. We confirm the form of the governing equation of the evolution suggested by Khokhlov (1995). The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. The results of our investigation provide the bases for revising and extending previous subgrid-scale model.

arXiv comment15 pages, 22 postscript figures. Accepted for publication by the Astrophysical Journal. High resolution figures can be found at http://flash.uchicago.edu/~zhang/research_paper.html

References in corpus (4)

• Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications
• Three-dimensional simulations of type Ia supernovae
• A localised subgrid scale model for fluid dynamical simulations in astrophysics II: Application to type Ia supernovae
• Off-Center Deflagrations In Chandrasekhar Mass SN Ia Models

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• Capturing the Fire: Flame Energetics and Neutronizaton for Type Ia Supernova Simulations
• Flame Evolution During Type Ia Supernovae and the Deflagration Phase in the Gravitationally Confined Detonation Scenario
• Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics
• The Deflagration Stage of Chandrasekhar Mass Models For Type Ia Supernovae: I. Early Evolution
• Type Ia supernova diversity: white dwarf central density as a secondary parameter in three-dimensional delayed detonation models
• Rayleigh-Taylor Unstable Flames -- Fast or Faster?
• Initiation of the detonation in the gravitationally confined detonation model of Type Ia supernovae
• Power-Law Wrinkling Turbulence-Flame Interaction Model for Astrophysical Flames
• Detonability of white dwarf plasma: turbulence models at low densities
• Rayleigh-Taylor unstable flames at higher Reynolds number
• Rayleigh-Taylor Unstable Flames: the Effect of Two-Mode Coupling