Session LQ: Reacting Flows III: Flames and Modeling

3:35 PM–5:45 PM, Monday, November 24, 2008
Room: 202B

Chair: Carlos Pantano, University of Illinois

Abstract ID: BAPS.2008.DFD.LQ.10

Abstract: LQ.00010 : Front propagation in vortex-dominated flows

5:32 PM–5:45 PM

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  Garrett O'Malley
    (Bucknell University)

  Justin Winokur
    (Bucknell University)

  Tom Solomon
    (Bucknell University)

We present experiments that explore how the propagation of a reaction front is affected by a two-dimensional flow dominated by vortices. The reaction is the excitable Belousov-Zhabotinsky chemical reaction. The flow is driven by the interaction between an electrical current passing through the fluid and a spatially-varying magnetic field produced by an array of magnets below the fluid. For some of the experiments, the forcing is strong enough to produce a weakly turbulent flow. Measurements are made both of the enhanced diffusion coefficient $D^*$ describing transport in the flow and of the propagation speed $v$ of a reaction front in the same flow. Scaling of $v$ versus $D^*$ is compared with that for the standard Fisher-Kolmogorov-Petrovsky-Piskunov prediction $v \sim \sqrt{D}$ (with $D$ as the molecular diffusion coefficient) for the reaction-diffusion limit with no fluid advection. We also study the effects of superdiffusive transport and L\'evy flights on front propagation in a time-dependent vortex array with wavy jet regions.

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