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 ...

The thermal instability of a rotating Rivlin-Ericksen viscoelastic fluid in the presence of uniform vertical magnetic field is considered. For the case of stationary convection, Rivlin-Ericksen viscoelastic fluid behaves like a Newtonian fluid. It is found that rotation has a stabilizing effect, whereas the magnetic field has both stabilizing and destabilizing effects. Graphs have been plotted ...

Fig. 1. Plot of the magnitude of the velocity (upper left) and axial component (x-direction) of the stress (upper right) of a steady viscoelastic fluid flow in a simple planar channel with an enlargement (motivated by a simple model of a small arterial aneurysm). This component of the stress is the most pronounced at the entrance and exit of the enlargement. The magnitude of the shear stress (c...

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...

While many fluid instabilities involving free surfaces are governed by interfacial forces the classic example being surface tension real materials often have surface forces produced by physical processes not present in the bulk. A striking example of this is a viscoelastic micellar fluid, in which the long tubelike aggregates form at low concentrations due to the presence of an organic salt/cos...

The thermal convection of compressible Walters’B′ Rotating viscoelastic fluid is considered in the presence of uniform vertical magnetic field. By applying normal mode analysis method, the dispersion relation has been derived and solved analytically. For stationary convection, Walters’B′ viscoelastic fluid behaves like an ordinary (Newtonian) fluid. It is found that rotation has a stabilizing e...

Large extensional deformations of viscoelastic fluid columns in filament stretching rheometers are studied through numerical simulations up to Hencky strains of greater than o=4. The time-dependent axisymmetric calculations incorporate the effects of viscoelasticity, surface tension, fluid inertia, plus a deformable free surface and provide quantitative descriptions of the evolution in the fila...

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...

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...