Fingering instabilities of a reactive micellar interface

Abstract

We present an experimental study of the fingering patterns in a Hele-Shaw cell, occurring when a gel-like material forms at the interface between aqueous solutions of a cationic surfactant cetyltrimethylammonium bromide) and an organic salt (salicylic acid), two solutions known to form a highly elastic wormlike micellar fluid when mixed homogeneously. A variety of fingering instabilities are observed, depending on the velocity of the front (the injection rate), and on which fluid is injected into which. We have found a regime of non-confined stationary or wavy fingers for which width selection seems to occur without the presence of bounding walls, unlike the Saffman-Taylor experiment. Qualitatively, some of our observations share common mechanisms with instabilities of cooling lava flows or growing biofilms.

7 pages, 9 figures, submitted to Phys. Rev. E, revised version

References in corpus (6)

• Fingering Instability in Combustion
• Oscillatory Motion of Rising Bubbles in Wormlike Micellar Fluids with Different Microstructures
• Motion of a Viscoelastic Micellar Fluid Around a Cylinder: Flow and Fracture
• Signature of elasticity in the Faraday instability
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Cited by in corpus (5)

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• Influence of a chemical reaction on viscous fingering: Effect of the injection flow rate