Fotini Labropulu

Steady Homann flow and heat transfer of an electrically conducting second grade fluid

The steady axisymmetric flow and heat transfer of an incompressible, electrically conducting non-Newtonian second grade fluid impinging on a flat plate is investigated. An external uniform, transverse magnetic field is applied at the surface of the plate. Similarity transformation is used to reduce the resulting highly nonlinear partial differential equations into ordinary differential equations. An effective numerical scheme has been adopted to solve the nonlinear ordinary differential equations. The effects of non-Newtonian flow parameters and the magnetic field on the momentum and thermal boundary layers are discussed in detail and shown graphically. It is interesting to find that the non-Newtonian parameter and the magnetic parameter have opposite effects on the momentum and thermal boundary layers. The skin friction coefficient decreases exponentially with an increase in the non-Newtonian viscoelastic parameter and increases linearly with an increase in the magnetic parameter.

Two-dimensional oblique stagnation-point flow towards a stretching surface in a viscoelastic fluid

In this paper, the steady two-dimensional stagnation-point flow of a viscoelastic Walters’ B’ fluid over a stretching surface is examined. It is assumed that the fluid impinges on the wall obliquely. Using similarity variables, the governing partial differential equations are transformed into a set of two non-dimensional ordinary differential equations. These equations are then solved numerically using the shooting method with a finite-difference technique.

Oblique Newtonian Fluid Flow with Heat Transfer Towards a Stretching Sheet

Oblique stagnation point flow and heat transfer towards a stretching sheet of a viscous fluid is investigated. The governing equations are transformed to a system of ordinary differential equations and then solved numerically for various values of the parameters. It is observed that the dual solution exists for velocity and temperature for certain values of velocity ratio parameter.

A comparison of Newtonian and non-Newtonian models for pulsatile blood flow simulations

Abstract Mathematical modeling of blood flows in the arteries is an important and challenging problem. This study compares several non-Newtonian blood models with the Newtonian model in simulating pulsatile blood flow through two three-dimensional models of an arterial stenosis and an aneurysm. Four non-Newtonian blood models, namely the Power Law, the Casson, the Carreau, and the Generalized Power Law, as well as the Newtonian model of blood viscosity, are used to investigate the flow effects induced by these different blood constitutive equations. The aim of this study is three-fold: firstly, to investigate the variation in wall shear stress in an artery with a stenosis or aneurysm at different flow rates and degrees of severity; secondly, to compare the various blood models and hence quantify the differences between the models and judge their significance; and lastly, to determine whether the use of the Newtonian blood model is appropriate over a wide range of shear rates.

Suction/Injection Effects on the Swirling Flow of a Reiner-Rivlin Fluid near a Rough Surface

The similarity equations for the Bodewadt flow of a non-Newtonian Reiner-Rivlin fluid, subject to uniform suction/injection, are solved numerically. The conventional no-slip boundary conditions are replaced by corresponding partial slip boundary conditions, owing to the roughness of the infinite stationary disk. The combined effects of surface slip ( ), suction/injection velocity ( ), and cross-viscous parameter ( ) on the momentum boundary layer are studied in detail. It is interesting to find that suction dominates the oscillations in the velocity profiles and decreases the boundary layer thickness significantly. On the other hand, injection has opposite effects on the velocity profiles and the boundary layer thickness.