Related Experiment Video
Updated: Jun 14, 2026

Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Saffman-Taylor instability of viscoelastic fluids: from viscous fingering to elastic fractures
1Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR 5587, Université Montpellier 2 and CNRS, Place Eugène Bataillon, F-34095 Montpellier Cedex, France. smora@univ-montp2.fr
Abstract:
We study the linear stability of an air front pushing on a viscoelastic upper convected Mawxell fluid inside a Hele-Shaw cell. Both theory and experiments involving several viscoelastic fluids prove that a unique dimensionless time parameter lambda[over] controls all elastic effects. For small values of lambda[over], Newtonian behavior dominates, while for higher values of lambda[over] viscoelastic effects appear. We show that the linear growth rate of a small initial perturbation diverges for a critical value lambda[over]=lambda(c)[over] approximately 10. Experiments prove that this divergence is associated to a fracturelike pattern instability of the interface. We conclude that the observed fractures come from the Saffman-Taylor instability and that they directly emerge from the linear regime of it.
Related Concept Videos
Plastic Behavior
Elastic Strain Energy for Shearing Stresses
Members Made of Elastoplastic Material
As the bending moment...
Stress-Strain Diagram - Brittle Materials
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Circular Shafts - Elastoplastic Materials
As torque on the...

