AAS Meeting #194 - Chicago, Illinois, May/June 1999
Session 86. Supernovae and Cataclysmic Variables
Display, Thursday, June 3, 1999, 9:20am-4:00pm, Southwest Exhibit Hall

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[86.13] Front propagation in pre-mixed material: approaches to modeling thermonuclear flames

Y. Young, J.C. Niemeyer, R. Rosner (U. of Chicago)

The interaction of thermonuclear fusion flames with turbulent flows is studied by means of incompressible DNS with a simplified flame description. This interaction plays an important role in flame propagation in Type Ia supernovae. The flame is treated as a single diffusive scalar field with a nonlinear source term (the nuclear reaction rate), and is characterized by the Prandtl number (Pr, the ratio of kinematic viscosity to thermal diffusivity and Pr \ll 1 in our cases), and laminar flame speed, SL. We simulate the propagation of such a flame through a stirred, turbulent velocity field, and study the increase of flame propagation speed due to turbulent mixing. A previous study (J.C. Niemeyer, W.K. Bushe, and G.R. Guetsch) shows that if SL \ge u\prime, where u\prime is the rms turbulent velocity fluctuation, the local flame propagation speed does not significantly deviate from SL even in the presence of velocity fluctuations on scales below the laminar flow thickness. The ratio SL/u\prime in this study is limited to values greater or closer to 1. In the present study, we perform the same simulation for SL/u\prime \ll 1 and compare results to the previous study.

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