We investigate the stability of steady planar stagnation flows of a dilute polyethylene oxide (PEO) solution using T-shaped microchannels. The precise flow rate control and well-defined geometries achievable with microfluidic fabrication technologies enable us to make detailed observations of the onset of elastically-driven flow asymmetries in steady flows with strong planar elongational charac...

In this work, particle-wall interaction in viscoelastic fluids is experimentally studied. The effect of Stokes number, Weissenberg number and surface roughness on the rebound velocity of a colliding spherical particle on a wall is considered. Different steel spherical particles are released in viscoelastic solutions of different high-molecular-weight polymers in water with different concentrati...

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...

This paper is devoted to the study of the two-dimensional flow of a Johnson-Segalman fluid in a planar channel having walls that are transversely displaced by an infinite, harmonic travelling wave of large wavelength. Both analytical and numerical solutions are presented. The analysis for the analytical solution is carried out for small Weissenberg numbers. (A Weissenberg number is the ratio of...

One of the newest of viscoelastic RANS turbulence models for drag reducing channel flow with polymer additives is studied in different flow and rheological properties. In this model, finitely extensible nonlinear elastic-Peterlin (FENE-P) constitutive model is used to describe the viscoelastic effect of polymer solution and turbulence model is developed in the k-ϵ-(ν^2 ) ̅-f framework. The geome...

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...

Microfluidics is very important in the world of BioMEMS, particularly for lab-ona-chip devices. There are many unusual differences from conventional fluidics, such as the significance of surface forces, the high shear/extensional rate, the high heat transfer rate, the low Reynolds number, and the high Weissenberg number. In this study, aqueous solutions of high molecular-weight polymers, polyet...

A new method for the simulation of 2D viscoelastic flow is presented. Numerical stability is obtained by the logarithmic-conformation change of variable, and a fully-implicit pure-streamfunction flow formulation, without use of any artificial diffusion. As opposed to other simulation results, our calculations predict a hydrodynamic instability in the 4:1 contraction geometry at a Weissenberg nu...

The rheology of solvent-filled polymer brushes under steady and oscillatory shear is studied by Brownian dynamics simulation. The flow field is solved self-consistently with the polymer dynamics. We find that under steady flow the brushes are shear thinning in both normal forces and shear viscosity. During oscillatory flow, extreme shear thickening occurs when the ratio of the Weissenberg numbe...