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Patterns and flow in frictional fluid dynamics.

Sandnes B, Flekkøy EG, Knudsen HA, Måløy KJ, See H - Nat Commun (2011)

Bottom Line: Here we consider Coulomb friction and compressibility in the fluid dynamics, and discover surprising responses including highly intermittent flow and a transition to quasi-continuous dynamics.Moreover, by varying the injection rate over several orders of magnitude, we characterize new dynamic modes ranging from stick-slip bubbles at low rate to destabilized viscous fingers at high rate.We classify the fluid dynamics into frictional and viscous regimes, and present a unified description of emerging morphologies in granular mixtures in the form of extended phase diagrams.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, New South Wales 2006, Australia. bjornar.sandnes@fys.uio.no

ABSTRACT
Pattern-forming processes in simple fluids and suspensions have been studied extensively, and the basic displacement structures, similar to viscous fingers and fractals in capillary dominated flows, have been identified. However, the fundamental displacement morphologies in frictional fluids and granular mixtures have not been mapped out. Here we consider Coulomb friction and compressibility in the fluid dynamics, and discover surprising responses including highly intermittent flow and a transition to quasi-continuous dynamics. Moreover, by varying the injection rate over several orders of magnitude, we characterize new dynamic modes ranging from stick-slip bubbles at low rate to destabilized viscous fingers at high rate. We classify the fluid dynamics into frictional and viscous regimes, and present a unified description of emerging morphologies in granular mixtures in the form of extended phase diagrams.

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Related in: MedlinePlus

Rate dependency.Displacement structures as a function of injection rate q. Frictional stick-slip flow at low rates gives way to continuous motion as viscous forces fluidize the accumulated front, and, at yet higher rates, suspends the granular material (ϕ=0.58, Vair=30 ml, scale bar, 10 cm). (Supplementary Movie 2).
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f4: Rate dependency.Displacement structures as a function of injection rate q. Frictional stick-slip flow at low rates gives way to continuous motion as viscous forces fluidize the accumulated front, and, at yet higher rates, suspends the granular material (ϕ=0.58, Vair=30 ml, scale bar, 10 cm). (Supplementary Movie 2).

Mentions: The rate dependency of the displacement patterning is probed in a series of experiments spanning four decades in the injection rate q (Fig. 4). Several new dynamic modes and morphologies emerge, and we classify these broadly into a frictional regime and a viscous regime.


Patterns and flow in frictional fluid dynamics.

Sandnes B, Flekkøy EG, Knudsen HA, Måløy KJ, See H - Nat Commun (2011)

Rate dependency.Displacement structures as a function of injection rate q. Frictional stick-slip flow at low rates gives way to continuous motion as viscous forces fluidize the accumulated front, and, at yet higher rates, suspends the granular material (ϕ=0.58, Vair=30 ml, scale bar, 10 cm). (Supplementary Movie 2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3104512&req=5

f4: Rate dependency.Displacement structures as a function of injection rate q. Frictional stick-slip flow at low rates gives way to continuous motion as viscous forces fluidize the accumulated front, and, at yet higher rates, suspends the granular material (ϕ=0.58, Vair=30 ml, scale bar, 10 cm). (Supplementary Movie 2).
Mentions: The rate dependency of the displacement patterning is probed in a series of experiments spanning four decades in the injection rate q (Fig. 4). Several new dynamic modes and morphologies emerge, and we classify these broadly into a frictional regime and a viscous regime.

Bottom Line: Here we consider Coulomb friction and compressibility in the fluid dynamics, and discover surprising responses including highly intermittent flow and a transition to quasi-continuous dynamics.Moreover, by varying the injection rate over several orders of magnitude, we characterize new dynamic modes ranging from stick-slip bubbles at low rate to destabilized viscous fingers at high rate.We classify the fluid dynamics into frictional and viscous regimes, and present a unified description of emerging morphologies in granular mixtures in the form of extended phase diagrams.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, New South Wales 2006, Australia. bjornar.sandnes@fys.uio.no

ABSTRACT
Pattern-forming processes in simple fluids and suspensions have been studied extensively, and the basic displacement structures, similar to viscous fingers and fractals in capillary dominated flows, have been identified. However, the fundamental displacement morphologies in frictional fluids and granular mixtures have not been mapped out. Here we consider Coulomb friction and compressibility in the fluid dynamics, and discover surprising responses including highly intermittent flow and a transition to quasi-continuous dynamics. Moreover, by varying the injection rate over several orders of magnitude, we characterize new dynamic modes ranging from stick-slip bubbles at low rate to destabilized viscous fingers at high rate. We classify the fluid dynamics into frictional and viscous regimes, and present a unified description of emerging morphologies in granular mixtures in the form of extended phase diagrams.

Show MeSH
Related in: MedlinePlus