Department of Electrical Engineering & Computer Science, North South University, Dhaka1229, Bangladesh
School of Chemistry, Physics & Mechanical Engineering, Queensland University of Technology, 2 George St., GPO Box 2434, Brisbane QLD 4001, Australia
Department of Mathematic, COMSATS Institute of Information Technology, Islamabad, Pakistan
Laminar magnetohydrodynamic (MHD) natural convection flow from an isothermal sphere immersed in a fluid with viscosity proportional to linear function of temperature has been studied. The governing boundary layer equations are transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations are reduced to convenient form which are solved numerically by two very efficient methods, namely, (i) Implicit finite difference method together with Keller box scheme and (ii) Direct numerical scheme. Numerical results are presented by velocity and temperature distribution, streamlines and isotherms of the fluid as well as heat transfer characteristics, namely the local skin-friction coefficients and the local heat transfer rate for a wide range of magnetohydrodynamic paramagnet and viscosity-variation parameter.