Monday, November 26, 2012

1211.5501 (Francesco Picano et al.)

Shear thickening in non-Brownian suspensions: an excluded volume effect    [PDF]

Francesco Picano, Wim-Paul Breugem, Dhrubaditya Mitra, Luca Brandt
Shear-thickening appears as an increase of the viscosity of a dense suspension with the shear rate, sometimes sudden and violent at high volume fraction. Its origin for non-colloidal suspension with non negligible inertial effects is still debated. Here we consider a simple shear flow and demonstrate that fluid inertia causes a strong microstructure anisotropy that results in the formation of a wake region with no relative flux of particles. We show that shear-thickening at finite inertia can be explained as an increase of the effective volume fraction when considering the dynamically excluded volume due to these wake regions.
View original: http://arxiv.org/abs/1211.5501

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