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The viscous fingering instability, which forms when a less-viscous fluid invades a more-viscous one within a confined geometry, is an iconic system for studying pattern formation. For both miscible and immiscible fluid pairs the growth dynamics change after the initial instability onset and the global structures, typical of late-time growth, are governed by the viscosity ratio. Here we introduce an experimental technique to measure flow throughout the inner and outer fluids. This probes the existence of a new length scale associated with the local pressure gradients around the interface and allows us to compare our results to the predictions of a previously proposed model for late-time finger growth. Published by the American Physical Society2024
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This content will become publicly available on April 3, 2027
Effect of translational shear on interfacial structure in the viscous fingering instability
We introduce applied shear as a method to control viscous fingering by smoothing the interface between miscible fluids. In the viscous fingering instability, a less viscous fluid displaces a more viscous one through the formation of fingers. The instability, which requires a confined geometry, is often studied in the thin gap of a quasi–two-dimensional Hele-Shaw cell. When the two fluids are miscible, the structures that form in the dimension traversing the gap are important for determining the instability onset. We demonstrate with experiments and simulations that oscillatory translational shear of the confining plates changes the gap-averaged viscosity profile so that it becomes less abrupt at the fingertips. Increasing the amplitude or velocity of the shear delays the instability onset and decreases the finger growth rate. Shear can thus be used to stabilize a pair of miscible fluids against fingering. The results show a direct correlation between a smoother viscosity profile and delayed instability.
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- Award ID(s):
- 2011854
- PAR ID:
- 10679370
- Publisher / Repository:
- American Association for the Advancement of Science
- Date Published:
- Journal Name:
- Science Advances
- Volume:
- 12
- Issue:
- 14
- ISSN:
- 2375-2548
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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