Unsteady laminar hydromagnetic flow and heat transfer in porous channels with temperature-dependent properties

The problem of unsteady laminar fully-developed flow and heat transfer of a n electrically-conducting and heat-generating or absorbing fluid with varia ble properties through porous channels in the presence of uniform magnetic and electric fields is formulated. The general governing equations which in clude such effects as magnetic, field, electric field, porous medium inerti a and heat generation or absorption effects are non-dimensionalized and sol ved numerically by the implicit finite-difference methodology. A representa tive set of numerical results for the transient and steady-state velocity a nd temperature profiles, the skin-friction coefficients at both the upper a nd lower walls of the channel as well as the heat transfer coefficient at t he lower wall are presented graphically and discussed. Favorable comparison s with previously published work are performed and the results are in excel lent agreement. A comprehensive parametric study is performed to show the e ffects of the Hartmann number, electric field parameter, inverse Darcy numb er, inertia parameter, heat generation or absorption coefficient, exponents of variable properties and the Eckert number on the solutions.