TY  - JOUR
AU  - Jin, H.
AU  - Kang, K.
AU  - Ahn, K. H.
AU  - Briels, Willem
AU  - Dhont, J. K. G.
TI  - Non-local stresses in highly non-uniformly flowing suspensions: The shear-curvature viscosity
JO  - The journal of chemical physics
VL  - 149
IS  - 1
SN  - 0021-9606
CY  - Woodbury, NY
PB  - American Institute of Physics
M1  - FZJ-2018-03629
SP  - 014903
PY  - 2018
AB  - For highly non-uniformly flowing fluids, there are contributions to the stress related to spatial variations of the shear rate, which are commonly referred to as non-local stresses. The standard expression for the shear stress, which states that the shear stress is proportional to the shear rate, is based on a formal expansion of the stress tensor with respect to spatial gradients in the flow velocity up to leading order. Such a leading order expansion is not able to describe fluids with very rapid spatial variations of the shear rate, like in micro-fluidics devices and in shear-banding suspensions. Spatial derivatives of the shear rate then significantly contribute to the stress. Such non-local stresses have so far been introduced on a phenomenological level. In particular, a formal gradient expansion of the stress tensor beyond the above mentioned leading order contribution leads to a phenomenological formulation of non-local stresses in terms of the so-called “shear-curvature viscosity”. We derive an expression for the shear-curvature viscosity for dilute suspensions of spherical colloids and propose an effective-medium approach to extend this result to concentrated suspensions. The validity of the effective-medium prediction is confirmed by Brownian dynamics simulations on highly non-uniformly flowing fluids.
LB  - PUB:(DE-HGF)16
C6  - pmid:29981556
UR  - <Go to ISI:>//WOS:000437708900028
DO  - DOI:10.1063/1.5035268
UR  - https://juser.fz-juelich.de/record/848388
ER  -