The unsteady flow and heat transfer in an incompressible laminar, electrically conducting
and non-Newtonian fluid over a non-isothermal stretching sheet with the
variation in the viscosity and thermal conductivity in a porous medium by the influence
of an external transverse magnetic field have been obtained and studied numerically.
By using similarity analysis the governing differential equations are
transformed into a set of non-linear coupled ordinary differential equations which
are solved numerically. Numerical results were presented for velocity and temperature
profiles for different parameters of the problem as power law parameter, unsteadiness
parameter, radiation parameter, magnetic field parameter, porous medium
parameter, temperature buoyancy parameter, Prandtl parameter, modified
Eckert parameter, Joule heating parameter, heat source/sink parameter, and others.
A comparison with previously published work has been carried out and the results
are found to be in good agreement. Also the effects of the pertinent parameters
on the skin friction and the rate of heat transfer are obtained and discussed numerically
and illustrated graphically.