This paper applies a diffuse-interface model to simulate the deformation of single drops in steady shear flows when one of the components is viscoelastic, represented by an Oldroyd-B model. In Newtonian fluids, drop deformation is dominated by the competition between interfacial tension and viscous forces due to flow. A fundamental question is how viscoelasticity in the drop or matrix phase inf...

in this paper, the flow of couple stress fluid is investigated in a helical screw rheometer (hsr). by unwrapping the channel, lands, and the outside rotating barrel, the geometry of hsr is approximated as a shallow infinite channel. both one- and two-dimensional analysis of the problem is presented using rectangular coordinates. in either case an exact solution of the flow problem is presented ...

A survey of secondary flows of viscoelastic liquids in straight tubes is given including recent work pointing at striking analogies with transversal deformations associated with the simple shearing of solid materials. The importance and implications of secondary flows of viscoelastic fluids in heat transfer enhancement are explored. Recent new work by the author and colleagues of both the stead...

Arterial stenosis, for example Atherosclerosis, is one of the most serious forms of arterial disease in the formation of which hemodynamic factors play a significant role. In the present study, a 3-D rigid carotid artery with axisymmetric stenosis with 75% reduction in cross-sectional area is considered. Laminar blood flow is assumed to have both Newtonian and non-Newtonian behavior (generalize...

the multiple reference frames (mrf) method is the most suitable method tosimulate impeller rotation in mixing systems. precise determination of stationaryand moving zones in mrf method leads to accurate results in mixing performance.in this research, the entire volume of mixing system was divided into two zones.the kinetic energy values were used to distinguish the zones with differentvelocitie...

The simulation of highly viscoelastic fluid flow problems is still plagued with the so-called high Weissenberg problem (HWP). The Weissenberg number We is the ratio of the magnitude of the elastic forces to that of the viscous forces. Most (if not all) numerical methods lose convergence i.e. fail to generate any result and/or fail to generate convergent solutions with respect to mesh size, at s...

background: the airway surface liquid (asl), which is a fluid layer coating the interior epithelial surface of the bronchi and bronchiolesis, plays an important defensive role against foreign particles and chemicals entering lungs. objective: numerical investigation has been employed to solve two-layer model consisting of mucus layer as a viscoelastic fluid and periciliary liquid layer as a newt...

Red blood cell hematocrit, aggregation and deformability, and plasma protein concentration influence the viscosity and elasticity of whole blood. These parameters affect the flow properties, especially at low shear rates (< 50 s(-1)). In particular, we have previously shown that the viscoelasticity of fluid affects the inlet filling characteristics and regions of flow separation in small pulsat...

We analyze the thermal convection thresholds and linear characteristics of the primary 1 and secondary instabilities for viscoelastic fluids saturating a porous horizontal layer heated from 2 below by a constant flux. Galerkin method is used to solve the eigenvalue problem by taking 3 into account the elasticity of the fluid, the ratio between the viscosity of the solvent and the total 4 viscos...

In order to investigate the rheological properties of viscoelastic fluids by mesoscopic hydrodynamics methods, we develop a multiparticle collision (MPC) dynamics model for a fluid of harmonic dumbbells. The algorithm consists of alternating streaming and collision steps. The advantage of the harmonic interactions is that the integration of the equations of motion in the streaming step can be p...