The objective of this chapter is to introduce and to illustrate the frequent and wide occurrence of non-Newtonian fluid behaviour in a diverse range of applications, both in nature and in technology. Starting with the definition of a nonNewtonian fluid, different types of non-Newtonian characteristics are briefly described. Representative examples of materials (foams, suspensions, polymer solut...

Flow field and heat transfer of a nanofluid, whose non-Newtonian behavior has been demonstrated in the laboratory, in a square enclosure have been numerically modeled and investigated. To estimate the viscosity of nanofluid, experimental data of Hong and Kim, 2012 have been used, and a new model has been proposed. Finally, the obtained results have been compared to those of Newtonian behavior. ...

Blood flow dynamics under physiologically realistic pulsatile conditions plays an important role in the growth, rupture, and surgical treatment of intracranial aneurysms. The temporal and spatial variations of wall pressure and wall shear stress in the aneurysm are hypothesized to be correlated with its continuous expansion and eventual rupture. In addition, the assessment of the velocity field...

The steady flow arising due to the rotation of a non-Newtonian fluid at a larger distance from a stationary disk is extended to the case where the disk surface admits partial slip. The constitutive equation of the non-Newtonian fluid is modeled by that for a Reiner-Rivlin fluid. The momentum equation gives rise to a highly nonlinear boundary value problem. Numerical solution of the governing no...

We investigate the flow patterns of Newtonian and viscoelastic fluids in microchannels containing bifurcations. The Newtonian fluid used as a reference is de-ionized water, while the non-Newtonian fluid used in the experiments has a shear rheology similar to that of human blood. The geometrical shape of the channels used reproduce bifurcating vessels, typically encountered in microcirculation n...

An investigation has been made to analyze the effects of viscous dissipation on the heat transfer characteristics for both hydro-dynamically and thermally fully developed, laminar shear driven flow between two infinitely long parallel plates, where the upper plate is moving in an axial direction at a constant speed. On the basis of some routine assumptions made in the literature, a close form a...

In this work, the fluid flow over a 2D backward-facing step is analyzed in order to provide a case study for the use of different models for the blood dynamic viscosity in COMSOL Multiphysics. Three non-Newtonian models, as well as the Newtonian model are used to study the shear stresses and the reattachment length as a function of the fluid speed. The nonNewtonian models used in this study are...

The growth rate of fingers of a Newtonian fluid can be modeled by a power law dependence on time. In this experiment, we examine whether the model can be adapted to describe a fluid with changing viscosity. We provide two possible interpretations. For PVA and a PVA/glycerol solution, we show that by assuming a constant exponent, the changing behavior of the fluid can be captured by a coefficien...

A porous media model is developed for non-Newtonian blood flow through reticulated foam at Reynolds numbers ranging from 10-8 to 10. This empirical model effectively divides the pressure gradient versus flow speed curve into three regimes, in which either the non-Newtonian viscous forces, the Newtonian viscous forces, or the inertial fluid forces are most prevalent. When compared to simulation ...

A computational fluid dynamics simulation study has been carried out for unsteady laminar flow in a planar 2D T-junction, using non-Newtonian viscoelastic fluids with characteristics similar to those of blood. In the large blood vessels, blood can be modelled as a Newtonian fluid, however in smaller vessels it exhibits non-Newtonian behaviour, showing a shear-thinning viscosity and, additionall...