TY - JOUR
T1 - Criterion for Fingering Instabilities in Colloidal Gels
AU - Divoux, Thibaut
AU - Shukla, Asheesh
AU - Marsit, Badis
AU - Kaloga, Yacouba
AU - Bischofberger, Irmgard
N1 - Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/6/19
Y1 - 2020/6/19
N2 - We sandwich a colloidal gel between two parallel plates and induce a radial flow by lifting the upper plate at a constant velocity. Two distinct scenarios result from such a tensile test: (i) stable flows during which the gel undergoes a tensile deformation without yielding, and (ii) unstable flows characterized by the radial growth of air fingers into the gel. We show that the unstable regime occurs beyond a critical energy input, independent of the gel's macroscopic yield stress. This implies a local fluidization of the gel at the tip of the growing fingers and results in the most unstable wavelength of the patterns exhibiting the characteristic scalings of the classical viscous fingering instability. Our work provides a quantitative criterion for the onset of fingering in colloidal gels based on a local shear-induced yielding in agreement with the delayed failure framework.
AB - We sandwich a colloidal gel between two parallel plates and induce a radial flow by lifting the upper plate at a constant velocity. Two distinct scenarios result from such a tensile test: (i) stable flows during which the gel undergoes a tensile deformation without yielding, and (ii) unstable flows characterized by the radial growth of air fingers into the gel. We show that the unstable regime occurs beyond a critical energy input, independent of the gel's macroscopic yield stress. This implies a local fluidization of the gel at the tip of the growing fingers and results in the most unstable wavelength of the patterns exhibiting the characteristic scalings of the classical viscous fingering instability. Our work provides a quantitative criterion for the onset of fingering in colloidal gels based on a local shear-induced yielding in agreement with the delayed failure framework.
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U2 - 10.1103/PhysRevLett.124.248006
DO - 10.1103/PhysRevLett.124.248006
M3 - Article
C2 - 32639838
AN - SCOPUS:85087661221
SN - 0031-9007
VL - 124
JO - Physical review letters
JF - Physical review letters
IS - 24
M1 - 248006
ER -