Hydromagnetic Flow and Heat Transfer in a Williamson Non-Newtonian Fluid from a Horizontal Circular Cylinder with Newtonian Heating

A theoretical and computational study of the magneto hydrodynamic flow and free convection heat transfer in an electro-conductive polymer on the external surface of a horizontal circular cylinder under radial magnetic field is presented. The Williamson viscoelastic model is employed which is representative of certain industrial polymers. Newtonian heating is incorporated via appropriate boundary conditions as this represents better actual thermal materials processing operations. The non-dimensional, transformed boundary layer equations for momentum and energy are solved with the second order accurate implicit Keller box finite difference method under appropriate boundary conditions. Validation of the numerical solutions is achieved via benchmarking with earlier published results. The influence of Weissenberg number (ratio of the relaxation time of the fluid and time scale of the flow), magnetic body force parameter, stream wise variable and Prandtl number on thermofluid characteristics are studied graphically and via tables. A weak elevation in temperature accompanies increasing Weissenberg number whereas a significant acceleration in the flow is computed near the cylinder surface with increasing Weissenberg number. Nusselt number is reduced with increasing Weissenberg number. Skin friction is increased whereas Nusselt number is reduced with greater stream wise coordinate. The study is relevant to smart coating transport phenomena.