Journal of Non-Newtonian Fluid Mechanics, Vol.192, 20-28, 2013
Non-isothermal flow of a Johnson-Segalman liquid in a lubricated pipe with wall slip
This work focuses on the unsteady, axi-symmetric, non-isothermal flow of a viscoelastic Johnson-Segalman liquid in a lubricated pipe which allows for wall slip. In simple,flows, the Johnson-Segalman constitutive model under certain conditions allows for a non-monotonic relationship between the shear stress and the rate of shear, hence, leading to shear banded flow phenomena. Wall slip has been conjectured to play a role or at least occur simultaneously with shear banding in certain cases. We investigate the relationships between wall slip and shear banding in non-isothermal pipe flow of a Johnson-Segalman fluid under axi-symmetric conditions and Arrhenius chemical kinetics. The wall slip in our investigation is postulated to arise, say, from wall lubrication; both constant and variable wall slip effects are here considered. The set of coupled non-linear time dependent partial differential equations for the fluid velocity, temperature and viscoelastic stresses are solved via semi-implicit finite difference techniques. We discuss the effect of wall slip on the flow profiles while varying certain flow and fluid material parameters. (C) 2012 Elsevier B.V. All rights reserved.
Keywords:Non-isothermal flow;Johnson-Segalman fluid;Shear banded flow;Wall slip;Arrhenius chemical kinetics;Finite difference method