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Bubble velocity in the nonlinear Rayleigh-Taylor instability at a deflagration front

M. Modestov ; V. Bychkov ; R. Betti ; Lars-Erik Eriksson (Institutionen för tillämpad mekanik, Strömningslära)
Physics of Plasmas (1070-664X). Vol. 15 (2008), 4, p. 12.
[Artikel, refereegranskad vetenskaplig]

The Rayleigh-Taylor instability at a deflagration front is studied systematically using extensive direct numerical simulations. It is shown that, for a sufficiently large gravitational field, the effects of bubble rising dominate the deflagration dynamics. It is demonstrated both analytically and numerically that the deflagration speed is described asymptotically by the Layzer theory in the limit of large acceleration. In the opposite limit of small and zero gravitational field, intrinsic properties of the deflagration front become important. In that case, the deflagration speed is determined by the velocity of a planar front and by the Darrieus-Landau instability. Because of these effects, the deflagration speed is larger than predicted by the Layzer theory. An analytical formula for the deflagration speed is suggested, which matches two asymptotic limits of large and small acceleration. The formula is in good agreement with the numerical data in a wide range of Froude numbers. The present results are also in agreement with previous numerical simulations on this problem.

Nyckelord: LARGE-EDDY SIMULATION, CONSISTENT STABILITY ANALYSIS, CURVED STATIONARY, FLAMES, NUMERICAL-SIMULATION, ABLATION FRONTS, RADIATED SOUND, TUBES, TURBULENT, PROPAGATION, SUPERNOVAE



Denna post skapades 2009-10-28. Senast ändrad 2016-08-17.
CPL Pubid: 100914

 

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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Strömningslära

Ämnesområden

Teknisk mekanik

Chalmers infrastruktur