The unsteady two-dimensional flow of a viscoelastic second-grade fluid impinging on an infinite plate is considered. The plate is making harmonic oscillations in its own plane. A finite difference technique is employed and solutions for small and large frequencies of the oscillations are obtained. 1. Introduction. In the past two decades, the importance of non-Newtonian viscoelastic liquids hav...

A computational fluid dynamics simulation study has been carried out for unsteady laminar flow in a planar 2D T-junction, using non-Newtonian viscoelastic fluids with characteristics similar to those of blood. In the large blood vessels, blood can be modelled as a Newtonian fluid, however in smaller vessels it exhibits non-Newtonian behaviour, showing a shear-thinning viscosity and, additionall...

This study aims to investigate the unsteady boundary-layer flow of a viscoelastic non-Newtonian fluid over a flat surface. The plate is suddenly jerked to move with uniform velocity in a uniform stream of non-Newtonian fluid. Purely analytic solution to governing nonlinear equation is obtained. The solution is highly accurate and valid for all values of the dimensionless time 0 ≤ τ < ∞. Flow pr...

the purpose of this research is to numerically investigate the interaction of pulsatile flow of blood with an axisymmetric artery in various percentages of stenosis. the carreau non-newtonian model and the generalized maxwell rheological model were used to model the blood fluid and the viscoelastic wall of arterial, respectively. the innovation of the present research is modeling of viscoelasti...

We present the dynamic velocity profiles of a Newtonian fluid (glycerol) and a viscoelastic Maxwell fluid (CPyCl-NaSal in water) driven by an oscillating pressure gradient in a vertical cylindrical pipe. The frequency range explored has been chosen to include the first three resonance peaks of the dynamic permeability of the viscoelastic-fluid--pipe system. Three different optical measurement t...

We investigate the flow patterns of Newtonian and viscoelastic fluids in microchannels containing bifurcations. The Newtonian fluid used as a reference is de-ionized water, while the non-Newtonian fluid used in the experiments has a shear rheology similar to that of human blood. The geometrical shape of the channels used reproduce bifurcating vessels, typically encountered in microcirculation n...

In this paper, we consider an infinitely long viscoelastic thread in a tube filled with a Newtonian fluid. We apply Jeffreys model as the rheological relation for the thread. The thread moves due to a constant pressure gradient, but so slowly that the quasi-static creeping flow approximation is applicable. We investigate the effect of the ratio of viscosities, fluid elasticity, confinement and ...

An analytical model is developed to study the viscoelastic micropolar fluid convection from an inclined plate as a simulation of electro-conductive polymer materials processing with nonlinear temperature. Jeffery’s viscoelastic model is deployed to describe the non-Newtonian characteristics of the fluid and provides a good approximation for polymers. Micro-structural is one of the characteristi...

In this paper, we will attempt to extract some principles concerning the flow-induced anisotropy which develops in the settling of particles in Newtonian and viscoelastic fluids. Our point-of-view is that the local microstructure, which is determined by the hydrodynamic interactions between neighboring particles, determines the global anisotropic structure of a fluidized suspension. The particl...

A transient molecular dynamics (TMD) method has been developed for simulation of fluid viscosity. In this method a sinusoidal velocity profile is instantaneously overlaid onto equilibrated molecular velocities, and the subsequent decay of that velocity profile is observed. The viscosity is obtained by matching in a least-squares sense the analytical solution of the corresponding momentum transp...