Rheo-PIV of a yield-stress fluid in a capillary with slip at the wall

Perez‐González, José; López-Durán, Juan Javier; Marín-Santibáñez, Benjamín M.; Rodríguez-González, Francisco

doi:10.1007/s00397-012-0651-9

Cited by 56 publications

(48 citation statements)

References 28 publications

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“…The main goal of the present * Electronic address: divoux@crpp-bordeaux.cnrs.fr Rapid Communication is to clarify the slip behavior of a jammed suspension of soft particles driven above the yield stress. Indeed in this case v s has been reported to increase as a quadratic function of σ in concentrated emulsions and microgels [11,23] while other experiments on similar samples rather led to a linear scaling of v s with σ [12,24,25].…”

Section: Introductionmentioning

confidence: 99%

Wall slip across the jamming transition of soft thermoresponsive particles

et al. 2015

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Flows of suspensions are often affected by wall slip, that is the fluid velocity v f in the vicinity of a boundary differs from the wall velocity vw due to the presence of a lubrication layer. While the slip velocity vs = |v f − vw| robustly scales linearly with the stress σ at the wall in dilute suspensions, there is no consensus regarding denser suspensions that are sheared in the bulk, for which slip velocities have been reported to scale as a vs ∝ σ p with exponents p inconsistently ranging between 0 and 2. Here we focus on a suspension of soft thermoresponsive particles and show that vs actually scales as a power law of the viscous stress σ − σc, where σc denotes the yield stress of the bulk material. By tuning the temperature across the jamming transition, we further demonstrate that this scaling holds true over a large range of packing fractions φ on both sides of the jamming point and that the exponent p increases continuously with φ, from p = 1 in the case of dilute suspensions to p = 2 for jammed assemblies. These results allow us to successfully revisit inconsistent data from the literature and paves the way for a continuous description of wall slip above and below jamming.

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Section: Introductionmentioning

confidence: 99%

Wall slip across the jamming transition of soft thermoresponsive particles

et al. 2015

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“…It is also interesting to note that before reaching the plateau the normalised width of the plug scales as W p /W ∝ ∆p −0.1 . This scaling is roughly an order of magnitude slower than that observed for a Carbopol gel, [30,31,32]…”

Section: Microscopic Flow Behaviour Of Chlorella Suspensions At Variomentioning

confidence: 68%

Microscopic flows of suspensions of the green non-motile Chlorella micro-alga at various volume fractions: Applications to intensified photobioreactors

Souliès

Pruvost

Castelain

et al. 2016

Journal of Non-Newtonian Fluid Mechanics

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International audienceAn experimental study of flows of the green non-motile Chlorella micro-alga in a plane micro-channel is presented. Depending on the value of the cell volume fraction, three distinct flow regimes are observed. For low values of the cell volume fraction a Newtonian flow regime characterised by a Poiseuille like flow field, absence of wall slip and hydrodynamic reversibility of the flow states is observed. For intermediate values of the cell volume fraction, the flow profiles are consistent with a Poiseuille flow of a shear thinning fluid in the presence of slip at the channel's wall. For even larger cell volume fractions, a yield stress like behaviour manifested through the presence of a central solid plug is observed. Except for the Newtonian flow regime, a strong hydrodynamic irreversibility of the flow and wall slip are found. The calculation of the wall shear rate and wall stress based on the measured flow fields allows one to identify the mechanisms of wall slip observed in the shear thinning and yield stress regimes

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“…Wall slip effects through a thin layer at the walls consisting of a less viscous (i.e. lower consistency index) grease than the bulk grease [6,23]. The lower consistency is by Barnes [3] suggested to be due to oil separation between the base oil and the grease thickener agent.…”

Section: Wall Slip and Flow Evolution In The Elbow Channelmentioning

confidence: 99%

Grease flow in an elbow channel

Westerberg

Farré-Lladós

et al. 2015

Tribol Lett

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Lubricating greases are materials characterized by a complex nonNewtonian rheology. This study is a continuation of previous studies on the coupling between grease rheology and grease flow in a straight channel-and concentric cylinder geometry. The problem has been modeled and validated with experiments. Here the flow in an elbow channel introducing a non-symmetric distribution of shear stress throughout the cross section of the channel elbow, as well as varying shear rates through the transition from the channel inlet to the outlet. The flow has been modeled both for higher flow rates and for creep flow. The influence of the grease rheology and flow conditions to wall slip, shear banding and an observed stick-slip type of motion observed for low flow rates are presented. The effect on the flow of the applied pressure is also investigated showing that the flow is sensitive to the pressure in the angular (ϕ) direction of the elbow. For high flow rates it is shown that flow separation occur with a resulting circulation in the elbow.

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Rheo-PIV of a yield-stress fluid in a capillary with slip at the wall

Cited by 56 publications

References 28 publications

Wall slip across the jamming transition of soft thermoresponsive particles

Wall slip across the jamming transition of soft thermoresponsive particles

Microscopic flows of suspensions of the green non-motile Chlorella micro-alga at various volume fractions: Applications to intensified photobioreactors

Grease flow in an elbow channel

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