Local transient rheological behavior of concentrated suspensions
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In this article, the shear transient response of concentrated non-Brownian suspensions is measured using a wide-gap Couette rheometer equipped with a particle image velocimetry device that allows measuring the velocity field.Abstract:
This paper reports experiments on the shear transient response of concentrated non-Brownian suspensions. The shear viscosity of the suspensions is measured using a wide-gap Couette rheometer equipped with a particle image velocimetry device that allows measuring the velocity field. The suspensions made of PMMA particles (31 μm in diameter) suspended in a Newtonian index- and density-matched liquid are transparent enough to allow an accurate measurement of the local velocity for particle concentrations as high as 50%. In the wide-gap Couette cell, the shear induced particle migration is evidenced by the measurement of the time evolution of the flow profile. A peculiar radial zone in the gap is identified where the viscosity remains constant. At this special location, the local particle volume fraction is taken to be the mean particle concentration. The local shear transient response of the suspensions when the shear flow is reversed is measured at this point where the particle volume fraction is well defin...read more
Citations
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References
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Journal ArticleDOI
Twenty years of particle image velocimetry
TL;DR: The development of the method of particle image velocimetry (PIV) is traced by describing some of the milestones that have enabled new and/or better measurements to be made.
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The shear-induced migration of particles in concentrated suspensions
TL;DR: In this article, it was shown that shear-induced migration of particles out of the sheared Couette gap and into the fluid reservoir, which reduces the particle concentration in the gap and thereby the observed viscosity, is consistent with a gap-limited shearinduced diffusion process normal to the plane of shear, with the relevant diffusion coefficient being proportional to the applied shear rate.
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A constitutive equation for concentrated suspensions that accounts for shear‐induced particle migration
TL;DR: In this article, a constitutive equation for computing particle concentration and velocity fields in concentrated monomodal suspensions is proposed that consists of two parts: a Newtonian constitutive equations in which the viscosity depends on the local particle volume fraction and a diffusion equation that accounts for shear-induced particle migration.
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Fluid mechanics and rheology of dense suspensions
TL;DR: In this paper, the authors review the fluid mechanics and rheology of dense suspensions, emphasizing investigations of microstructure and total stress, and explore scaling theories and the development of constitutive equations.