Effective front propagation in steady cellular flows: A least time criterion.
We experimentally study the propagation of a reaction front in a chain of counter-rotating vortices. The front is induced by an autocatalytic chemical reaction in an aqueous solution stirred by electroconvective means. The front propagates by getting quickly engulfed in a vortex and by slowly crossing the separatrix to the next vortex. Its mean velocity along the chain increases with the flow intensity but shows both a bending and a dependence on the vortex aspect ratio. We recover these features within a kinematic model of front propagation by seeking the quickest front path through a vortex.
Pocheau
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IRPHE, CNRS et Universités Aix-Marseille I & II, 49 rue Joliot-Curie, B.P. 146, Technopôle de Château-Gombert, F-13384 Marseille, Cedex 13, France.
Harambat
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