in this study prediction of the steady-state flow of branched polymer melts in pipe geometry with finite volume method is presented. our analysis in this study revealed that;for normal-stress tqq , the xpp model can predict this tensor unlike the other viscoelastic models such as ptt or gieskus which can not predict tqq for viscoelastic fluid in two dimensional pipe flows. the fluid is modelled...

in this study we consider pcf (plane couette flow) which is introduced by two parallel planes which have same velocity in opposite direction and the distance between them is filled by viscoelastic fluid. by this way we have modeled viscoelastic damper. the constitutive equation of js (johnson-segalman) has been used for dynamic analysis of viscoelastic damper’s behavior. by using this equation ...

in this paper, the transient inertial viscoelastic flow around a circular cylinder is investigated numerically. a second order finite-volume method is used to increase the numerical accuracy. here, the giesekus model is used as the constitutive equation. this nonlinear model has prominent ability in describing normal stress differences and viscosity in power-law regions. the impacts of the elas...

high weissenberg boundary layer flow of viscoelastic fluids on a stretching surface has been studied. the flow is considered to be steady and two dimensional. flows of viscoelastic liquids at high weissenberg number exhibit stress boundary layers near walls. these boundary layers are caused by the memory of the fluid. upon proper scaling and by means of an exact similarity transformation, the n...

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...

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...

this paper presents a numerical simulation of developing flow and heat transfer of a viscoelastic fluid in a rectangular duct. in fully developed flow of a viscoelastic fluid in a non-circular duct, secondary flows normal to the flow direction are expected to enhance the rate of heat and mass transfer. on the other hand, properties such as viscosity, thermal conductivity, specific heat and rela...

Recently, Hashin-Shtrikman bounds for bulk and shear moduli of elastic composites have been extended to the moduli of composite viscoelastic media. Since viscoelastic moduli are complex, the viscoelastic bounds form a closed curve on a complex plane. We apply these general viscoelastic bounds to a particular case of a porous solid saturated with a Newtonian fluid. Our analysis shows that for po...

Experimental observations are reported for the laminar flow of a viscoelastic liquid through a symmetrical plane sudden expansion preceded by a gradual contraction from a square duct. As is well known, for Newtonian fluid flow above a critical Reynolds number the flowfield downstream of an expansion becomes asymmetric. For the viscoelastic liquid investigated here the asymmetry is greatly reduc...

In micro-channels, the flow of viscous liquids e.g. water, is laminar due to the low Reynolds number in miniaturized dimensions. An aqueous solution becomes viscoelastic with a minute amount of polymer additives; its flow behavior can become drastically different and turbulent. However, the molecules are typically invisible. Here we have developed a novel visualization technique to examine the ...