Negative electrorheological responses induced by micro-particle electrorotation in two-dimensional Couette flow geometries are analyzed by a set of continuum modeling field equations originating from anti-symmetric/couple stress theories in the finite spin viscosity small spin velocity (FSV) limit. Analytical solutions are obtained for the first time to express the spin velocity, linear velocit...

In this study, predictive capabilities of apparent viscosity of oil-based drilling fluids which is used in National Iranian South Oilfields Company (NISOC) were evaluated using Newtonian and non-Newtonian models to drive a new suitable equation. The non-Newtonian models include Bingham plastic, Power law, Herschel-Bulkley, Casson, and Robertson-Stiff. To validate the results, the calculated vis...

We study the periodic time dependence of shear stress that occurs in a low- and a high-density fluid in a molecular dynamics algorithm for simulation of constant shear flow. We present a generalization of the linear response theory for a case when the equilibrium relaxation function and the equilibrium shear stress depend on strain. The predictions of this generalization reveal that the time de...

We investigate the rheology of dilute dispersions of fumed colloidal particles with attractive interactions in hydrocarbon liquids. Surprisingly, these systems display shear thickening due to the breakdown of densified flocs and a concomitant increase in the effective volume fraction of the fractal particles in the fluid. We show that this shear thickening is controlled by a critical stress and...

Background: The study of rheological properties of blood has special interest since it is a circulating fluid exposed to shear rates during its life time. This work aims to investigate the influence of whole body gamma irradiation on the rheological properties of rat’s blood. The applied shear rate was from 12 to 375 s-1. Low shear viscosity (up to 100 s-1) depends mainly on the erythroc...

We write down and solve equations describing steady state, optically thin, advection-dominated accretion onto a Kerr black hole. The mean flow, described by the relativistic fluid equations, is axisymmetric and vertically averaged. The effect of turbulence in the flow is represented by a viscous shear stress. Our treatment differs in several important ways from earlier work: we use a causal pre...

Interacting fluids, endowed with bulk viscous stresses, are discussed in a unified perspective with the aim of generalizing the treatment of cosmological perturbation theory to the case where both fluctuating decay rates and fluctuating bulk viscosity coefficients are simultaneously present in the relativistic plasma. A gauge-invariant treatment of the qualitatively new phenomena arising in thi...

Attractive emulsions near the colloidal glass transition are investigated by rheometry and optical microscopy under shear. We find that (i) the apparent viscosity eta drops with increasing shear rate, then remains approximately constant in a range of shear rates, then continues to decay; (ii) the first normal stress difference N1 transitions sharply from nearly zero to negative in the region of...

We investigated the effects of particle shape on shear thickening in densely packed suspensions. Rods of different aspect ratios and nonconvex hooked rods were fabricated. Viscosity curves and normal stresses were measured using a rheometer for a wide range of packing fractions for each shape. Suspensions of each shape exhibit qualitatively similar discontinuous shear thickening. The logarithmi...