A generic nonlinear Maxwell model for the stress tensor in viscoelastic materials is studied under mixing scenarios in a three-dimensional steady lid-driven cavity flow. Resulting laminar and turbulent flow profiles are investigated to study their mixing efficiencies. Massless tracer particles and passive concentrations are included to show that the irregular spatio-temporal chaos, present in t...

Micro–macro simulations of polymeric solutions rely on the coupling between macroscopic conservation equations for the fluid flow and stochastic differential equations for kinetic viscoelastic models at the microscopic scale. In the present work we introduce a novel micro–macro numerical approach, where the macroscopic equations are solved by a finite-volume method and the microscopic equation ...

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...

Lung mechanics and morphometry were assessed in two groups of nine normal open-chest rabbits mechanically ventilated (MV) for 3-4 h at zero end-expiratory pressure (ZEEP) with physiological tidal volumes (Vt; 11 ml/kg) and high (group A) or low (group B) inflation flow (44 and 6.1 ml x kg(-1) x s(-1), respectively). Relative to initial MV on positive end-expiratory pressure (PEEP; 2.3 cmH(2)O),...

handling of endodontic sealers is greatly dependent on their elasticity and flow ability. we compared the viscoelastic properties of three root canal sealers.ah plus (dentsply, de trey, konstanz, germany), endofill (dentsply hero, petrópolis, rio de janeiro, brazil) and ah26 (dentsply, de trey, konstanz, germany) were mixed according to the manufacturers' instructions. the resulted pastes were ...

a theoretical solution is presented for the forced convection heat transfer of a viscoelastic fluid obeying the giesekus constitutive equation in a concentric annulus under steady state, laminar, and purely tangential flow. a relative rotational motion exists between the inner and the outer cylinders, which induces the flow. a constant temperature was set in both cylinders, in this study. the f...

The study aims at quantifying the effect of fluid elasticity on frictional pressure drop for the flow of viscoelastic fluid through a helical coil. Aqueous solutions of polyacrylamide (PAA) in the concentration range 0.25 %–0.5 % (wt/vol.) were used as test fluids. The fluids were characterized using dynamic rheometer under rotational and oscillatory modes. The rheological study depicts that th...

A mathematical model of unsteady non-Newtonian blood flow in an artery under stenotic condition has been developed. The flowing blood is considered to be a viscoelastic fluid characterized by the Oldroyd-B model and the arterial wall is considered to be rigid, having cosine-shaped stenosis. The governing equations of motion accompanied by appropriate choice of the initial and boundary condition...

We consider a fourth-order eigenvalue problem on a semi-infinite strip which arises in the study of viscoelastic shear flow. The eigenvalues and eigenfunctions are computed by a spectral method involving Laguerre functions and Legendre polynomials.

We present a numerical study of a stabilization method for computing confined and free-surface flows of highly elastic viscoelastic fluids. In this approach, the constitutive equation based on the conformation tensor, which is used to define the viscoelastic model, is modified introducing an evolution equation for the square-root conformation tensor. Both confined and free-surface flows are con...