Normal stresses and free surface deformation in concentrated suspensions of noncolloidal spheres in a viscoelastic fluid

Zarraga, Isidro E.; Hill, Davide A.; Leighton, David T.

doi:10.1122/1.1396356

Cited by 64 publications

(40 citation statements)

References 19 publications

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“…The rheology of dense suspensions of solid particles in an isodense fluid of viscosity η f is Newtonian at small shear rateγ with a viscosity τ /γ diverging as η f (φ c − φ) −β , as the particle volume fraction goes to its critical value φ c . The measured exponent β ranges between 2 and 3 [1,[13][14][15]. Mean field theory assuming a dissipation dominated by lubrication films separating particles predicts an exponent β = 1 [9].…”

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confidence: 99%

Transition from the Viscous to Inertial Regime in Dense Suspensions

2012

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Non-Brownian suspensions present a transition from Newtonian behaviour in the zero-shear limit to a shear thickening behaviour at a large shear rate, none of which is clearly understood so far. Here, we carry out numerical simulations of such an athermal dense suspension under shear, at an imposed confining pressure. This setup is conceptually identical to the recent experiments of Boyer and co-workers [1]. Varying the interstitial fluid viscosities, we recover the Newtonian and Bagnoldian regimes and show that they correspond to a dissipation dominated by viscous and contact forces respectively. We show that the two rheological regimes can be unified as a function of a single dimensionless number, by adding the contributions to the dissipation at a given volume fraction.

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confidence: 99%

Transition from the Viscous to Inertial Regime in Dense Suspensions

2012

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“…Using these non conventional rheological tools (rotating-rod and tiltedtrough), the value is found too close to zero to determine whether it is negative, positive or null within experimental accuracy. Some experiments using more conventional rheometry find that N 1 is quite small and negative [10][11][12][13], while others report positive values [14]. Some recent studies point to the effect of polydispersity [15] and of confinement [16] which may explain these discrepancies.…”

Section: Suspension Viscositymentioning

confidence: 83%

Rheology of dense suspensions of non colloidal particles

Guazzelli

2017

EPJ Web Conf.

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Abstract. Dense suspensions are materials with broad applications both in industrial processes (e.g. waste disposal, concrete, drilling muds, metalworking chip transport, and food processing) and in natural phenomena (e.g. flows of slurries, debris, and lava). Despite its long research history and its practical relevance, the mechanics of dense suspensions remain poorly understood. The major difficulty is that the grains interact both by hydrodynamic interactions through the liquid and by mechanical contact. These systems thus belong to an intermediate regime between pure suspensions and granular flows. We show that we can unify suspension and granular rheology under a common framework by transferring the frictional approach of dry granular media to wet suspensions of spherical particles. We also discuss non-Newtonian behavior such as normal-stress differences and shear-induced migration. Beyond the classical problem of dense suspension of hard spheres which is far from being completely resolved, there are also entirely novel avenues of study concerning more complex mixtures of particles and fluids such as those involving other types of particles (e.g. fibers) or non-Newtonian fluids that we will also address.

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“…If the solvent is viscoelastic, the non-Newtonian behavior of the suspension is affected by the particle microstructure. The onset of shear thinning in the viscosity and the normal stress differences N 1 and N 2 shifts with increasing particle volume fraction [7][8][9]. While shear thinning behavior of colloidal suspension has been well studied, it is found that in non-colloidal Newtonian suspensions (with particles diameter 2a > 1 lm for which Brownian motion is negligible), shear thinning also occurs at Pe ) 1 [3,4,10].…”

Section: Introductionmentioning

confidence: 96%