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Stick-slip instability for viscous fingering in a gel

N. Puff·G. Debregeas·J. -M. di Meglio·D. Higgins·C. Wagner·D. Bonn
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Abstract

The growth dynamics of an air finger injected in a visco-elastic gel (a PVA/borax aqueous solution) is studied in a linear Hele-Shaw cell. Besides the standard Saffmann-Taylor instability, we observe - with increasing finger velocities - the existence of two new regimes: (a) a stick-slip regime for which the finger tip velocity oscillates between 2 different values, producing local pinching of the finger at regular intervals, (b) a ``tadpole'' regime where a fracture-type propagation is observed. A scaling argument is proposed to interpret the dependence of the stick-slip frequency with the measured rheological properties of the gel.

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N. Puff, G. Debregeas, J. -M. di Meglio, D. Higgins, C. Wagner, D. Bonn. 2002-01-09. Stick-slip instability for viscous fingering in a gel. https://doi.org/10.1209/epl%2Fi2002-00427-7

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