Flowing resistance and dilatancy of dense suspensions: lubrication and repulsion

Rognon, Pierre; Einav, Itai; Gay, Cyprien

doi:10.1017/jfm.2011.397

Cited by 25 publications

(17 citation statements)

References 52 publications

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“…(4) is not sufficient to extract the values of both η µ and η c . To resolve this problem, we assume the normal stress in this regime is purely frictional such that τ c ≈ µ c τ N 0 [24], where τ N 0 is the measured normal stress amplitude (see Fig.3 (d)), and η c = µ c τ N 0 /ωγ 0 . Thus, in the large-strain regime, we calculate η µ = |η | − µ c τ N 0 /ωγ 0 from Eq.…”

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confidence: 99%

Shear thickening in highly viscous granular suspensions

Majumdar

Brown

et al. 2014

EPL

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We experimentally investigate shear thickening in dense granular suspensions under oscillatory shear. Directly imaging the suspension-air interface, we observe dilation beyond a critical strain γc and the end of shear thickening as the maximum confining stress is reached and the contact line moves. Analyzing the shear profile, we extract the viscosity contributions due to hydrodynamics ηµ, dilation ηc and sedimentation ηg. While ηg governs the shear thinning regime, ηµ and ηc together determine the shear thickening behavior. As the suspending liquid's viscosity varies from 10 to 1000 cst, ηµ is found to compete with ηc and soften the discontinuous nature of shear thickening.PACS numbers:

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confidence: 99%

Shear thickening in highly viscous granular suspensions

Majumdar

Brown

et al. 2014

EPL

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“…The other parameters in the model are: G p , assumed to be equal to the shear modulus of an agarose gel disk, shown in Table 6.1; Poisson's ratio (ν) of 0.45 is estimated for 5 % agarose microgels and ν = 0.38 was estimated for 1.5 % agarose. ; and the number of nearest neighbours, n = 10 as determined by Rognon et al (2011) through discrete element simulation of packed suspensions of non-colloidal elastic spheres. Poisson's ratio is estimated based on the literature suggesting ν of hydrogels is dependent on cross-link density and falls in the range 0.38 to 0.49 (Chippada et al, 2010, Chen et al, 2013.…”

Section: Viscoelastic Solid-like Behaviour Above Jammingmentioning

confidence: 99%

Rheology of soft particle suspensions

Shewan¹

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The purpose of this work is to investigate the effect of particle elasticity on suspension rheology and flow. Non-colloidal (~ 10 µm) spherical agarose microgels suspended in water are used as a model system. The advantage of these microgels is that they are manufactured to a specific elastic modulus, ranging from 8 to 300 kPa, determined from the modulus of an agarose gel disk. This is in contrast to routinely studied colloidal microgels where the particle modulus cannot be established. Colloidal microgel modulus and specific volume are variable as they are responsive to suspension conditions (such as, pH, temperature and osmotic pressure). Using experimental rheology, an investigation was carried out into the liquid and solid-like behaviour of agarose microgel suspensions. Suspension concentration regimes from dilute to densely packed were investigated to show explicitly the effect of particle modulus on rheology, which becomes increasingly more significant with increasing phase volume. In addition, particle modulus is shown to influence two shear flow characteristics -slip and shear thickening.To interpret suspension viscosity as a function of phase volume the model, developed by Maron and Pierce (1956) and popularised by Quemada (1977) (MPQ model), is applied. This model is based on a scaling relation of the pair distribution function and predicts the critical phase volume at which the viscosity tends to infinity, corresponding to when spherical particles are randomly close packed (φ rcp ).Commonly, it is used empirically by free fitting of experimental data to obtain the critical phase volume. In this work, a method has been developed to use the MPQ model in accordance with its theoretical basis by independently predicting φ rcp from the particle size distribution. It is shown that this theoretical form of the MPQ model, with no adjustable parameters, results in an accurate prediction (within experimental uncertainty, ± 5 %) of the viscosity-phase volume relationship for hard spheres. In addition, alterations in suspension microstructure (for example, through particle aggregation) or rheological artefacts (such as, particle migration) are readily identified by plotting the MPQ model in a linear form.In contrast to hard spheres, the phase volume of agarose microgels is difficult to define accurately. The approach typically used in literature, and used here, is to iii define the specific volume from dilute suspension viscosity. This approach can be corroborated using the theoretical viscosity-phase volume model validated with hard sphere suspensions. The specific volume of agarose microgels is easily defined at φ rcp using the particle size distribution. From this approach it is discovered that, in the viscous regime, below φ rcp , particle elasticity does not explicitly affect suspension viscosity. However, it is shown that particle elasticity has an indirect effect on viscosity at phase volumes between ~ 0.4 and φ rcp due to limited re-swelling during microgel preparation procedures.When microgels c...

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“…So, no specific surfactant was considered. Using a generalized repulsive force that increases steeply when the particles come in close relative positions to each other has been done in Soft Dynamics [27,29] and the direct force used here is deployed in a similar manor. The Lennard-Jones potential included with LAMMPS [30] was used as the direct force.…”

Section: Bubble Interaction Modelingmentioning

confidence: 99%

The Influence of Bubbles on Foamed Cement Viscosity Using an Extended Stokesian Dynamics Approach

Rosenbaum

Massoudi

Dayal

2019

Fluids

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We want to study the influence of bubbles on the viscosity of suspensions with a computational approach that also accounts for the arrangement of the bubbles due to shearing flow. This requires a large number of bubbles to properly simulate and requires a large amount of computational resources. Here we develop a set of equations to define the viscosity ratio from the simulation results to show the influence of the bubbles on the viscosity as a function of the volume fraction. One application of this work has been used to study a specific type of cement that has bubbles injected into the slurry while it is still fluid. The bubbles are added to reduce the density but they also improve the properties of the cement with the increase in viscosity. We show that the computed results match the few experimental results that have been reported.

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Flowing resistance and dilatancy of dense suspensions: lubrication and repulsion

Cited by 25 publications

References 52 publications

Shear thickening in highly viscous granular suspensions

Shear thickening in highly viscous granular suspensions

Rheology of soft particle suspensions

The Influence of Bubbles on Foamed Cement Viscosity Using an Extended Stokesian Dynamics Approach

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