Local determination of the constitutive law of a dense suspension of noncolloidal particles through magnetic resonance imaging

By G. Ovarlez, F. Bertrand, S. Rodts. 2005

271 citations recorded by the source corpus.

We investigate the flowing behavior of dense suspensions of noncolloidal particles, by coupling macroscopic rheometric experiments and local velocity and concentration measurements through magnetic resonance imaging (MRI) techniques. We find that the flow is localized at low velocities, and that the material is inhomogeneous; the local laws inferred from macroscopic rheometric observations must then be reinterpreted in light of these local observations. We show that the short time response to a velocity step allows dense suspensions to be characterized locally: they have a purely viscous behavior, without any observable influence of granular friction. In the “jammed” zone, there may be a contact network, whereas in the sheared zone there are only hydrodynamic interactions: localization consists of a change in configuration at the grain scale. From the concentration and velocity profiles, we provide for the first time local measurements of the concentration dependence of viscosity, and find a Krieger-Dough...

Subfields: Fluid Flow and Transfer Processes, Materials Chemistry, Physical and Theoretical Chemistry

View Paper: https://www.semanticscholar.org/paper/17ebf2129084c94a17005e8736c6f38863159409

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Citations in the corpus

Homogenization approach to the behavior of suspensions of noncolloidal particles in yield stress fluids (2008, background): “This value is very close to the value ϕm = 0.605 measured locally very recently in dense suspensions of noncolloidal particles in Newtonian fluids by Ovarlez et al. (2006) through MRI techniques.”
Refractive-index and density matching in concentrated particle suspensions: a review (2011, methodology): “These results are in agreement with MRI measurements (Ovarlez et al. 2006).”
Phenomenology and physical origin of shear localization and shear banding in complex fluids (2009, methodology): “However, experiments performed in a controlled stress mode reveal that they undergo a viscosity bifurcation (Huang et al. 2005, Ovarlez et al. 2006) below the apparent yield stress: no flow seems to be allowed below a critical shear rate.”
A review of microstructure in concentrated suspensions and its implications for rheology and bulk flow (2009, methodology): “Ovarlez et al. (2006) used detailed nuclear magnetic resonance imaging (NMRI) to capture the flow and concentration profiles within the interior of a widegap Couette flow and showed that, owing to particle migration, it is necessary to consider the local variables to properly model the constitutive”
Shear thickening of cornstarch suspensions (2012, background): “ning is always accompanied by particle migration (Fall et al, 2010). In Couette flows, the consequence of migration is an excess of particles near the outer cylinder [Leighton and Acrivos (1987a, b), Ovarlez et al. (2006), Huang and Bonn (2007)]. However our measurements do not completely rule out p”
Yield stress and elastic modulus of suspensions of noncolloidal particles in yield stress fluids (2008, background): “…Graham et al. (1991); Phillips et al. (1992); Nott and Brady (1994); Mills and Snabre (1995); Morris and Boulay (1999); Shapley et al. (2004); Ovarlez et al. (2006)] but is still badly known in yield stress fluids (some studies exist however in viscoelastic fluids [Tehrani (1996); Huang and…”
On the existence of a simple yield stress fluid behavior (2012, methodology): “during a transient, consistently with the Divoux et al. [46] observations. 3.1.2. Impact of particle migration Particle migration can also be a cause for the apparent lack of a local constitutive law [17]. Indeed, when various τ(~r),γ˙(~r) data are combined to build a constitutive law, a hidden hypo”
Effect of Coarse Particle Volume Fraction on the Yield Stress and Thixotropy of Cementitious Materials (2008, background): “[36] that 160 radial migration occurs as an almost instantaneous and unavoidable process in 161 a Couette geometry.”
Rheology of sheared suspensions of rough frictional particles (2014, unknown): “Experimental studies have conﬁrmed that suspension viscosity ⌘ s increases with φ and diverges as φ approaches a maximal fraction φ m about 0.6 (Ovarlez et al. 2006).”
Dense suspensions in rotating-rod flows: normal stresses and particle migration (2011, background): “In fact, the present rotating-rod geometry is simply the limiting case of wide-gap Couette flow for which particle migration away from the rotating inner cylinder has long been reported in the literature (Gadala-Maria & Acrivos 1980; Abott, Tetlow & Graham 1991; Tetlow 1998; Ovarlez et al. 2006).”