title: Autocatalytic reaction fronts inside a porous medium of glass spheres.
abstract: We analyze experimentally chemical wave propagation in the disordered flow field of a porous medium. The reaction fronts travel at a constant velocity that drastically depends on the mean flow direction and rate. The fronts may propagate either downstream and upstream but, surprisingly, they remain static over a range of flow rate values. Resulting from the competition between the chemical reaction and the disordered flow field, these frozen fronts display a particular sawtooth shape. The frozen regime is likely to be associated with front pinning in low velocity zones, the number of which varies with the ratio of the mean flow and the chemical front velocities.
authors.affiliation: Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris, France and Université Paris-Sud, CNRS, Laboratoire FAST, Bâtiment 502, Campus Universitaire, Orsay F-91405, France.
authors.forename: Severine
authors.initials: S
authors.lastname: Atis
authors.affiliation: Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris, France and Université Paris-Sud, CNRS, Laboratoire FAST, Bâtiment 502, Campus Universitaire, Orsay F-91405, France.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Saha
authors.affiliation: Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris, France and Université Paris-Sud, CNRS, Laboratoire FAST, Bâtiment 502, Campus Universitaire, Orsay F-91405, France.
authors.forename: Harold
authors.initials: H
authors.lastname: Auradou
authors.affiliation: Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris, France and Université Paris-Sud, CNRS, Laboratoire FAST, Bâtiment 502, Campus Universitaire, Orsay F-91405, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Salin
authors.affiliation: Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris, France and Université Paris-Sud, CNRS, Laboratoire FAST, Bâtiment 502, Campus Universitaire, Orsay F-91405, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Talon