Thermally activated transitions are ubiquitous in nature, occurring complex environments which typically conceived as ideal viscous fluids. We report the first direct observations of a Brownian bead transiting between wells bistable optical potential viscoelastic fluid with single long relaxation time. precisely characterize both and fluid, thus enabling neat comparison our experimental results...

1. Introduction The motion of a spherical particle through a fluid with non-Newtonian rheological properties is a well-studied problem with a broad range of practical application from sedimentation of muds and slurries to processing of filled polymer melts. As a benchmark problem for computational rheology and the evaluation of numerical codes (cf. Hassager, 1988), the sedimentation of a sphere...

Peristaltic motion of viscoelastic incompressible fluid in an axisymmetric tube with a sinusoidal wave is studied theoretically in the case that the radius of the tube is small relative to the wavelength. Oldroyd flow has been considered in this study and the problem is formulated and analyzed using a perturbation expansion in terms of the variation of the wave number. This analysis can model t...

The flow field around a sphere falling at its terminal velocity in a column of viscoelastic non-shear-thinning fluid is experimentally measured with digital particle image velocimetry. The working fluid is an extensively characterized, monodisperse, polystyrene based Boger fluid. The sphere radius relative to the radius of the column of fluid is small (a/rc50.083). The Weissenberg number (lUt /...

The analysis of a new viscometer that takes the form of an oscillating plate, fabricated from silicon using the methods of micro-electro-mechanical-systems (MEMS) is considered. The instrument is designed principally for experimental use in the oil industry. The plate is 1.6mm wide, 2.4mm long, and 20μm thick. It is suspended from a 0.4mm thick support by 48 square cross-section legs, each of l...

We analyze the steady non-Newtonian fluid–structure interaction between flow of an Oldroyd-B fluid and a deformable channel. Specifically, we provide theoretical framework for calculating leading-order effect fluid’s viscoelasticity on rate–pressure drop relation deformation channel’s elastic wall. first identify characteristic scales dimensionless parameters governing in slender shallow channe...

The rheological behaviour of ethylene glycol-based nanofluids containing hexagonal scalenohedral-shaped α-Fe2O3 (hematite) nanoparticles at 303.15 K and particle weight concentrations up to 25% has been carried out using a cone-plate Physica MCR rheometer. The tests performed show that the studied nanofluids present non-Newtonian shear-thinning behaviour. In addition, the viscosity at a given s...

The liquid filament microrheometer originally described by Bazilevsky et al. (1990) provides a simple way of extracting material parameters for Newtonian and viscoelastic fluids from measurements of the capillary breakup of a thin fluid thread. However, there is an unresolved discrepancy in the value of the Newtonian viscosity obtained from the experimental data when using the existing theoreti...

The paper shows the successive steps of approximation of Picard unification for the solution of the non-isothermal fluid flow in thin layer including inertia forces and apparent viscosities described by the non-linear dependences. In this paper is presented a unified semi analytical method of solution of the asymmetrical, laminar, steady and unsteady, non-Newtonian lubrication problem flow betw...