Stick-slip instability for viscous fingering in a gel

N. Puff (1) , G. Debregeas (2) , J.-M. Di Meglio , D Higgins , D. Bonn (3) , C. Wagner (4)

1 ICS - Institut Charles Sadron
2 LJP - Laboratoire Jean Perrin
3 LPS - Laboratoire de Physique Statistique de l'ENS
4 iSTeP - Institut des Sciences de la Terre de Paris

Non-Newtonian fluid flows. PACS. 82.70.Gg-Gels and sols. PACS. 83.60.Wc-Flow instabilities. 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.

Domaines: Biophysique [physics.bio-ph]

N. Puff, G. Debregeas, J.-M. Di Meglio, D Higgins, D. Bonn, et al.. Stick-slip instability for viscous fingering in a gel. EPL - Europhysics Letters, 2002, 58 (4), pp.524-529. ⟨10.1209/epl/i2002-00427-7⟩. ⟨hal-02506697⟩