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 an electrically‐conducting and heat‐generating or absorbing fluid with variable properties through porous channels in the presence of uniform magnetic and electric fields is formulated. The general governing equations which include such effects as magnetic field, electric field, porous medium inertia and heat generation or absorption effects are non‐dimensionalized and solved numerically by the implicit finite‐difference methodology. A representative set of numerical results for the transient and steady‐state velocity and temperature profiles, the skin‐friction coefficients at both the upper and lower walls of the channel as well as the heat transfer coefficient at the lower wall are presented graphically and discussed. Favorable comparisons with previously published work are performed and the results are in excellent agreement. A comprehensive parametric study is performed to show the effects of the Hartmann number, electric field parameter, inverse Darcy number, inertia parameter, heat generation or absorption coefficient, exponents of variable properties and the Eckert number on the solutions.