Poiseuille flow of dense non-colloidal suspensions: The role of intergranular and nonlocal stresses in particle migration

Monsorno, Davide; Varsakelis, Christos; Papalexandris, Miltiadis

doi:10.1016/j.jnnfm.2017.08.002

Cited by 20 publications

(3 citation statements)

References 40 publications

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“…Treatments of such geometries have also been carried out using theories of granular rheology including those relating to the viscous number and kinetic theory [24][25][26][27][28][29][30][31] . Study of Poiseuillestyle flow of grains on the other hand is somewhat limited to being either driven by gravity, for instance dry grains falling through a channel 32,33 , or in the complete absence of it, where pressure-driven density-matched grains in suspension exhibit Bingham-style plug flow velocity profiles similar to yield stress fluids 26,34,35 .…”

Section: Introductionmentioning

confidence: 99%

Self-similar velocity profiles and mass transport of grains carried by fluid through a confined channel

et al. 2020

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Confined fluid-driven granular flows are present in a plethora of natural and industrial settings yet even the most fundamental of these are not completely understood. While widely-studied grain flows such as bed load and density-matched Poiseuille flow have been observed to exhibit exponential and Bingham style velocity profiles respectively, this work finds that a fluid-driven bed of non-buoyant grains filling a narrow horizontal channel -confined both from the sides and above -exhibits self-similar Gaussian velocity profiles. As the imposed flow rate is increased and the grain velocity increases, the Gaussian flow profiles penetrate deeper into the packing of the channel. Filling fractions were observed to also be self-similar and qualitatively consistent with granular theory relating to the viscous number I, which at a given position on the self-similar Gaussian curve is found to be generally constant regardless of imposed flow rate or velocity magnitude. An empirical description of the flow is proposed, and local velocity and filling fraction measurements were used to obtain local grain flux and accurately recover a total grain flow rate.

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Section: Introductionmentioning

confidence: 99%

Self-similar velocity profiles and mass transport of grains carried by fluid through a confined channel

et al. 2020

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“…The former assumes that particle migration occurs due to variations in normal stress, while the latter targets the differences in shear rate as the main reason. The suspension balance model is considered to be a more generalized approach; however, the diffusive flux model is often preferred due to its simplicity and relatively high accuracy [26][27][28].…”

Section: Pumping Of Concrete-modeling As Two Immiscible Single-phase mentioning

confidence: 99%

Experimental Insights into Concrete Flow-Regimes Subject to Shear-Induced Particle Migration (SIPM) during Pumping

2020

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In this paper, the authors have focused on shear-induced particle migration (SIPM), its effect on concrete flow patterns, and lubricating layer formation during pumping. For this purpose, various volume-fractions ϕ of aggregates were selected. The particle migration was analyzed by applying two methods: sampling hardened concrete exposed to pumping and performing X-ray microcomputed tomography (μCT) and image analysis to determine the thickness of the lubricating layer due to SIPM. The results indicate that the first approach is unsuitable due to the nearly equal molecular density of particles and matrix. The second approach indicated that the actual thickness of the lubricating layer depends on the discharge rate as well as on ϕ and viscosity of concrete bulk; hence, it cannot be defined as a constant parameter for all concrete mixtures. Additionally, the concrete pipe-flow pattern, i.e., plug versus shear flow, was captured and studied while considering pumping pressure and discharge rate. It was concluded that particle migration is essential in the cases of both flowable and very flowable concretes with a high volume-fraction of solids. The changes in rheological properties caused by SIPM are severe enough to influence the definition of the flow pattern as plug or shear and the discharge rate of pumped concrete as well.

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“…It turns out, indeed, that the hematocrit ϕ should be cusp-shaped at the centerline, a behavior never observed in real experiments. These difficulties can be overcome by means of a more sophisticated strategy as that recently developed by Monsorno et al [ 36 , 37 ], Lecampion and Garagash [ 38 ], Boyer et al [ 39 ], and Ahnert et al [ 40 ], where blood is treated as mixture. However, the related mathematical problem to solve shows a high degree of complexity mainly due to the boundary conditions to select.…”

Section: Introductionmentioning

confidence: 99%

A continuum mechanics model for the Fåhræus-Lindqvist effect

2021

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The decrease in apparent relative viscosity that occurs when blood is made to flow through a tube whose diameter is less than about 0.3 mm is a well-known and documented phenomenon in physiology, known as the Fåhræus-Lindqvist effect. However, since the historical work of Fåhræus and Lindqvist (Amer. J. Physiol. 96(3): pp. 562–568, 1931), the underlying physical mechanism has remained enigmatic. A widely accepted qualitative explanation was provided by Haynes (Amer. J. Physiol. 198, pp. 1193–1200, 1960) according to which blood flows in microvessels with a core-annulus structure, where the erythrocytes concentrate within a central core surrounded by a plasma layer. Although sustained by observations, this conjecture lacks a rigorous deduction from the basic principles of continuum dynamics. Moreover, relations aimed to reproduce the blood apparent relative viscosity, extensively used in micro-circulation, are all empirical and not derived from the analysis of the fluid mechanical phenomena involved. In this paper, we apply the recent results illustrated in Guadagni and Farina (Int. J. Nonlinear Mech. 126, p. 103587, 2020), with the purpose of showing that Haynes’ conjecture, slightly corrected to make it more realistic, can be proved and can be used to reach a sound explanation of the Fåhræus-Lindqvist effect based on continuum mechanics. We propose a theoretical model for the blood apparent relative viscosity which is validated by matching not only the original experimental data reported by Fåhræus and Lindqvist (Amer. J. Physiol. 96(3), pp. 562–568, 1931), but also those provided by several subsequent authors.

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Poiseuille flow of dense non-colloidal suspensions: The role of intergranular and nonlocal stresses in particle migration

Cited by 20 publications

References 40 publications

Self-similar velocity profiles and mass transport of grains carried by fluid through a confined channel

Self-similar velocity profiles and mass transport of grains carried by fluid through a confined channel

Experimental Insights into Concrete Flow-Regimes Subject to Shear-Induced Particle Migration (SIPM) during Pumping

A continuum mechanics model for the Fåhræus-Lindqvist effect

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