We determine both experimentally and numerically the onset of elastic flow instabilities in viscoelastic polymer solutions with different levels of shear thinning. Previous experiments realized in microfluidic serpentine channels using dilute polymeric solutions showed that the onset of elastic instabilities strongly depends on the channel curvature. The scaling dependence is well captured by t...

Using molecular dynamics simulations, we study the lubricating properties of neutral and charged bottle-brush coatings as a function of the compression and shear stresses and brush grafting density. Our simulations have shown that in charged bottle-brush systems under shear there is a layer with excess counterions located in the middle between brush-bearing surfaces. The main deformation mode o...

Assessment of the potential of a polymer flood for mobility control requires an accurate model on the viscosities of displacement fluids involved in the process. Because most polymers used in EOR exhibit shear-thinning behavior, the effective viscosity of a polymer solution is a highly nonlinear function of shear rate. A reservoir simulator including the model for the shear-rate dependence of v...

We determine the linear viscoelastic response of jammed packings of athermal repulsive viscous spheres, a model for emulsions, wet foams, and soft colloidal suspensions. We numerically measure the complex shear modulus, a fundamental characterization of the response, and demonstrate that low frequency response displays dynamic critical scaling near unjamming. Viscoelastic shear response is gove...

We report results of simulations of a model for concentrated aggregated colloidal dispersions under shear flows. In an effort to study trends in rheology for varying colloidal interactions, we study a reduced hydrodynamic, frame-invariant, pair-drag model in which a long-range, many-body mobility matrix is generated just from resistance pair-drag terms that include lubrication. The model also i...

The tear film on the front of the eye is critical to proper eyesight; in many mathematical models of the tear film, the tear film is assumed to be on a flat substrate. We re-examine this assumption by studying the effect of a substrate which is representative of the human cornea. We study the flow of a thin fluid film on a prolate spheroid which is a good approximation to the shape of the human...

Rheological characterization of physically crosslinked peptide- and protein-based hydrogels is widely reported in the literature. In this review, we focus on solid injectable hydrogels, which are commonly referred to as 'shear-thinning and rehealing' materials. This class of what sometimes also are called 'yield-stress' materials holds exciting promise for biomedical applications that require w...

A two-dimensional Yukawa liquid is studied using two different nonequilibrium molecular dynamics simulation methods. Shear viscosity values in the limit of small shear rates are reported for a wide range of Coulomb coupling parameter and screening lengths. At high shear rates it is demonstrated that this liquid exhibits shear thinning; i.e., the viscosity eta diminishes with increasing shear ra...