Fahraeus-Lindqvist e ect in an Oldroyd 8-constant uid

A pressure driven axisymmetric ow in a circular tube, having a non- Newtonian Oldroyd 8-constant uid in the core, is considered in this paper. The Oldroyd 8-constant uid is surrounded by a Newtonian uid in the present study. The exact solution of the governing equation is obtained in the form of an integral which is evaluated using Gaussian quadrature. The expression for the apparent viscosity is obtained. The graphical results are presented for the proles of apparent viscosity for dierent values of the material parameters plotted against tube radius. It is found that for all the values of the material parameters, the apparent viscosity decreases as the tube radius decreases which is the Fahraeus-Lindqvist eect. The results for the case, when there is no Newtonian uid present in the periphery, are also deduced.