Slippery questions about complex fluids flowing past solids

Granick, Steve; Zhu, Yunhua; Lee, Hyunjung

doi:10.1038/nmat854

Cited by 380 publications

(353 citation statements)

References 47 publications

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“…It is reported in sedimentation studies [16] that slip was not observed in vacuum conditions but only when the liquid sample was in contact with air. Furthermore, the study in [63] showed that tetradecane saturated with CO 2 lead to results consistent with no-slip but significant slip when saturated with argon, whereas the opposite behavior was observed for water. Similar results were reported in [161].…”

Section: Dissolved Gas and Bubblesmentioning

confidence: 93%

Microfluidics: The No-Slip Boundary Condition

Lauga

Brenner

Stone

2007

Springer Handbook of Experimental Fluid Mechanics

591

674

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The no-slip boundary condition at a solid-liquid interface is at the center of our understanding of fluid mechanics. However, this condition is an assumption that cannot be derived from first principles and could, in theory, be violated. In this chapter, we present a review of recent experimental, numerical and theoretical investigations on the subject. The physical picture that emerges is that of a complex behavior at a liquid/solid interface, involving an interplay of many physico-chemical parameters, including wetting, shear rate, pressure, surface charge, surface roughness, impurities and dissolved gas.

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Section: Dissolved Gas and Bubblesmentioning

confidence: 93%

Microfluidics: The No-Slip Boundary Condition

Lauga

Brenner

Stone

2007

Springer Handbook of Experimental Fluid Mechanics

591

674

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“…A number of new studies have confirmed the existence of a liquid slip over certain solid surfaces, as summarized in recent reviews. [5][6][7] Although a few studies 8,9 have reported a slip over hydrophilic surfaces, many theoretical, 10,11 experimental, [12][13][14][15][16][17][18][19][20][21][22][23] and numerical 24 studies have reported that hydrophobic surfaces allow a noticeable slip ranging from nanometers to a micron in "slip length" ͑the linearly extrapolated distance into a solid surface at which a no-slip condition would hold true͒. Several reasons have been proposed for the slip over hydrophobic surfaces, including a molecular slip, 10 a decrease in the viscosity of the boundary layer, 11 the small dipole moment of a polar liquid, 23 and a gas gap or nanobubbles at the liquid-surface interface.…”

Section: Introductionmentioning

confidence: 99%

Effective slip and friction reduction in nanograted superhydrophobic microchannels

Choi¹,

Ulmanella²,

Kim³

et al. 2006

Physics of Fluids

412

266

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Enabled by a technology to fabricate well-defined nanogrates over a large area ͑2 ϫ 2 cm 2 ͒, we report the effect of such a surface, in both hydrophilic and hydrophobic conditions, on liquid slip and the corresponding friction reduction in microchannels. The grates are designed to be dense ͑ϳ230 nm pitch͒ but deep ͑ϳ500 nm͒ in order to sustain a large amount of air in the troughs when the grates are hydrophobic, even under pressurized liquid flow conditions ͑e.g., more than 1 bar͒. A noticeable slip ͑i.e., slip length of 100-200 nm, corresponding to 20%-30% reduction of pressure drop in a ϳ3 m high channel͒ is observed for water flowing parallel over the hydrophobic nanogrates; this is believed to be an "effective" slip generated by the nanostrips of air in the grate troughs under the liquid. The effective slip is clearer and larger in flows parallel to the nanograting patterns than in transverse, suggesting that the nanograted superhydrophobic surfaces would not only reduce friction in liquid flows under pressure but also enable directional control of the slip. This paper is the first to use nanoscale grating patterns and to measure their effect on liquid flows in microchannels.

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“…Such an apparent slip introduces a larger velocity difference at the boundary while the fluid speed seems (but in fact does not) to extrapolate to zero below the surface (Granick et al, 2004;Forster and Smith, 2010). In this model, an apparent slip is enabled when adding the boundary condition "wetted wall".…”

Section: Model Domains and Initial Model Set-upmentioning

confidence: 99%

Development of a numerical workflow based on <i>μ</i>-CT imaging for the determination of capillary pressure–saturation-specific interfacial area relationship in 2-phase flow pore-scale porous-media systems: a case study on Heletz sandstone

Peche¹,

Halisch²,

Tatomir³

et al. 2016

Solid Earth

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Abstract. In this case study, we present the implementation of a finite element method (FEM)-based numerical porescale model that is able to track and quantify the propagating fluid-fluid interfacial area on highly complex microcomputed tomography (µ-CT)-obtained geometries. Special focus is drawn to the relationship between reservoir-specific capillary pressure (p c ), wetting phase saturation (S w ) and interfacial area (a wn ). The basis of this approach is highresolution µ-CT images representing the geometrical characteristics of a georeservoir sample. The successfully validated 2-phase flow model is based on the Navier-Stokes equations, including the surface tension force, in order to consider capillary effects for the computation of flow and the phase-field method for the emulation of a sharp fluid-fluid interface.In combination with specialized software packages, a complex high-resolution modelling domain can be obtained. A numerical workflow based on representative elementary volume (REV)-scale pore-size distributions is introduced. This workflow aims at the successive modification of model and model set-up for simulating, such as a type of 2-phase problem on asymmetric µ-CT-based model domains. The geometrical complexity is gradually increased, starting from idealized pore geometries until complex µ-CT-based pore network domains, whereas all domains represent geostatistics of the REV-scale core sample pore-size distribution. Finally, the model can be applied to a complex µ-CT-based model domain and the p c -S w -a wn relationship can be computed.

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Slippery questions about complex fluids flowing past solids

Cited by 380 publications

References 47 publications

Microfluidics: The No-Slip Boundary Condition

Microfluidics: The No-Slip Boundary Condition

Effective slip and friction reduction in nanograted superhydrophobic microchannels

Development of a numerical workflow based on <i>μ</i>-CT imaging for the determination of capillary pressure–saturation-specific interfacial area relationship in 2-phase flow pore-scale porous-media systems: a case study on Heletz sandstone

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Slippery questions about complex fluids flowing past solids

Cited by 380 publications

References 47 publications

Microfluidics: The No-Slip Boundary Condition

Microfluidics: The No-Slip Boundary Condition

Effective slip and friction reduction in nanograted superhydrophobic microchannels

Development of a numerical workflow based on &lt;i&gt;μ&lt;/i&gt;-CT imaging for the determination of capillary pressure–saturation-specific interfacial area relationship in 2-phase flow pore-scale porous-media systems: a case study on Heletz sandstone

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Development of a numerical workflow based on <i>μ</i>-CT imaging for the determination of capillary pressure–saturation-specific interfacial area relationship in 2-phase flow pore-scale porous-media systems: a case study on Heletz sandstone