Engineered transparent emulsion to optically study particulate flows in yield stress fluids

Rashedi, Ahmadreza; Ovarlez, Guillaume; Hormozi, Sarah

doi:10.1007/s00348-019-2858-3

Cited by 3 publications

(4 citation statements)

References 51 publications

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“…2016; Baroudi et al. 2020; Rashedi, Ovarlez & Hormozi 2020). In the case of dilute suspension, if the Reynolds number is low, the particles follow the streamlines, otherwise, in high Reynolds, particles migrate to specific locations in the flow cross-section.…”

Section: Literature Reviewmentioning

confidence: 99%

Torque scaling at primary and secondary bifurcations in a Taylor–Couette flow of suspensions

2022

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The Taylor–Couette flow of non-colloidal, neutrally buoyant spherical particle suspensions in the $\phi =0\,\%-28\,\%$ concentration range and (17–250) Reynolds number ( $\mathcal {R})$ range is studied using synchronized flow visualization and torque measurements. Both methods are applied in ramp-up/down (acceleration/deceleration of the inner cylinder) experiments to detect the various flow structure states and bifurcation natures, their critical conditions and their lifetime in $\mathcal {R}$ range. Torque measurement allows us to discuss the evolution of the (pseudo) Nusselt number, $\mathcal {N}$ , and friction coefficient with $\mathcal {R}$ or alternatively the Taylor number, Ta. Flow visualization brings additional information on the unsteady dynamics of flow states. For concentrations higher than $\phi =6\,\%$ , two unsteady (spiral vortex flow, wavy vortex flow) and one steady (Taylor vortex flow) flow state are observed in both ramp-up/down experiments. Hysteretic behaviour is reported for some primary, secondary and tertiary bifurcations, which are thus found to be subcritical. A critical concentration is observed at $\phi =15\,\%$ for the range of $\mathcal {R}$ at which spiral vortex flow is encountered. Characteristic frequencies of unsteady flow state (spiral vortex flow, wavy vortex flow) for different suspension concentrations are evaluated. Finally, three hydrodynamic concentration subregimes are identified for the first time, with their distinct sets of concentration-dependent critical conditions, torque scaling exponents and friction coefficients.

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Section: Literature Reviewmentioning

confidence: 99%

Torque scaling at primary and secondary bifurcations in a Taylor–Couette flow of suspensions

2022

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“…8,9,30 Our recent effort in understanding the fracturing flows 5 has led us to contribute to the field. 10,[37][38][39][40][41] This paper aims to add to the existing literature by providing well-resolved experimental data on the shear-induced migration and axial development of particles in channel flows of non-Brownian suspensions. This study, along with other recent data in the field, may serve as a basis for improving and refining available model frameworks for non-Brownian suspensions.…”

Section: Several Modeling and Computational Approaches Have Been Takenmentioning

confidence: 99%

“…In summary, it has been shown that the recent computational and experimental data cannot fully be explained by the available model frameworks 8,9,30 . Our recent effort in understanding the fracturing flows 5 has led us to contribute to the field 10,37‐41 . This paper aims to add to the existing literature by providing well‐resolved experimental data on the shear‐induced migration and axial development of particles in channel flows of non‐Brownian suspensions.…”

Section: Introductionmentioning

confidence: 99%

Shear‐induced migration and axial development of particles in channel flows of non‐Brownian suspensions

et al. 2020

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We present an experimental study on the shear-induced migration and axial development of particles in the channel flows of non-Brownian suspensions. The suspending fluid is Newtonian. We investigate fracturing flows with a Hele-Shaw type scaling through building a unique channel setup and an advanced optical system. The local particle concentration profiles are measured via the refractive-index matching technique for a wide range of bulk volume fraction, that is, 0:1 ≤ ϕ b ≤ 0:5. Simultaneously, the particle image velocimetry is performed to determine the velocity profile of the particle phase. We compare our experimental results with the available two-phase continuum frameworks and show discrepancies and similarities in the fully developed and axial development of the solid volume fraction profiles. We discuss directions in which the continuum frameworks require improvements.

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“…The best known feature is the divergence of shear viscosity, η, when the solid volume fraction, φ, tends to a maximum value known as the jamming volume fraction, φ m . However, the range of complex rheological behaviours can also include the occurrence of a yield stress (Dagois-Bohy et al 2015;Ovarlez et al 2015), shear-thinning (Vázquez-Quesada, Tanner & Ellero 2016; Lobry et al 2019) or shear-thickening behaviours (Barnes 1989;Mari et al 2014;Guy, Hermes & Poon 2015;Comtet et al 2017;Madraki et al 2017;Madraki, Ovarlez & Hormozi 2018;Madraki et al 2020), normal stress differences, irreversibility under oscillating shear (Pine et al 2005;Blanc, Peters & Lemaire 2011a), shear-induced microstructure (Gadala-Maria & Acrivos 1980;Blanc et al 2011aBlanc et al , 2013 and particle migration (Phillips et al 1992;Snook, Butler & Guazzelli 2016;Sarabian et al 2019;Rashedi, Ovarlez & Hormozi 2020).…”

Section: Introductionmentioning

confidence: 99%

The role of rolling resistance in the rheology of wizarding quidditch ball suspensions

d'Ambrosio,

Koch,

Hormozi

2023

J. Fluid Mech.

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To elucidate the effect of particle shape on the rheology of a dense, viscous suspension of frictional, non-Brownian particles, experimental measurements are presented for suspensions of polystyrene particles with different shapes in the same solvent. The first suspension is made of spheres whereas the particles which compose the second suspension are globular but with flattened faces. We present results from steady shear and shear-reversal rheological experiments for the two suspensions over a wide range of stresses in the viscous regime. Notably, we show that the rheology of the two suspensions is characterised by a shear-thinning behaviour, which is stronger in the case of the suspension of globular particles. Since the shear-reversal experiments indicate an absence of adhesive particle interactions, we attribute the shear thinning to a sliding friction coefficient which varies with stress as has been observed previously for systems similar to the first suspension. We observe that the viscosity of the two suspensions is similar at high shear stress where small sliding friction facilitates particle relative motion due to sliding. At lower shear stress, however, the sliding friction is expected to increase and the particle relative motion would be associated with rolling. The globular particles attain a higher viscosity at low shear stress than the spherical particles. We attribute this difference to a shape-induced resistance to particle rolling that is enhanced by the flattened faces. Image analysis is employed to identify features of the particle geometry that contribute to the resistance to rolling. It is shown that the apparent rolling friction coefficients inferred from the rheology are intermediate between the apparent dynamic and static rolling friction coefficients predicted on the basis of the image analysis. All three rolling resistance estimates are larger for the globular particles with flat faces than for the spherical particles and we argue that this difference yields the stronger shear thinning of the globular particle suspension.

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Engineered transparent emulsion to optically study particulate flows in yield stress fluids

Cited by 3 publications

References 51 publications

Torque scaling at primary and secondary bifurcations in a Taylor–Couette flow of suspensions

Torque scaling at primary and secondary bifurcations in a Taylor–Couette flow of suspensions

Shear‐induced migration and axial development of particles in channel flows of non‐Brownian suspensions

The role of rolling resistance in the rheology of wizarding quidditch ball suspensions

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