Effects of magnetic field and partial slip on unsteady axisymmetric flow of Carreau nanofluid over a radially stretching surface

The unsteady magnetohydrodynamic (MHD) axisymmetric flow of Carreau nanofluid over a radially stretching sheet is investigated numerically in this article. Recently devised model for nanofluid namely Buongiorno's model incorporating the effects of Brownian motion and thermophoresis is adopted here. Additionally, partial velocity slip and convective boundary condition are considered. Mathematical problem is modeled with the help of momentum, energy and nanoparticles concentration equations using suitable transformation variables. The numerical solutions for the transformed highly nonlinear ordinary differential equations are computed for both shear thinning and shear thickening fluids. For numerical computations, an effective numerical approach namely the Runge-Kutta Felhberg integration scheme is adopted. Effects of involved controlling parameters on the temperature and nanoparticles concentration are examined. Numerical computations for the local Nusselt number and local Sherwood number are also performed. It is interesting to note that the strong magnetic field has the tendency to enhance the thermal and concentration boundary layer thicknesses. Additionally, the local Nusselt and Sherwood numbers depreciate by improving values of unsteadiness parameter, magnetic parameter, velocity slip parameter and thermophoresis parameter in shear thickening and shear thinning fluids. (C) 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.