Bubble velocity in the nonlinear Rayleigh-Taylor instability at a deflagration front
2008 (English)In: Physics of Plasmas, ISSN 1070-664X, Vol. 15, no 4, 042703-042715 p.Article in journal (Refereed) Published
The Rayleigh-Taylor instability at a deflagration front is studiedsystematically using extensive direct numerical simulations. Itis shown that, for a sufficiently large gravitational field, theeffects of bubble rising dominate the deflagration dynamics. Itis demonstrated both analytically and numerically that thedeflagration speed is described asymptotically by the Layzertheory in the limit of large acceleration. In the opposite limitof small and zero gravitational field, intrinsic properties of thedeflagration front become important. In that case, the deflagrationspeed is determined by the velocity of a planar front and by theDarrieus-Landau instability. Because of these effects, thedeflagration speed is larger than predicted by theLayzer theory. An analytical formula for the deflagration speedis suggested, which matches two asymptotic limits of large andsmall acceleration. The formula is in good agreement withthe numerical data in a wide range of Froude numbers. Thepresent results are also in agreement with previous numericalsimulations on this problem.
Place, publisher, year, edition, pages
2008. Vol. 15, no 4, 042703-042715 p.
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:umu:diva-23085DOI: 10.1063/1.2901191OAI: oai:DiVA.org:umu-23085DiVA: diva2:219636