mhd unsteady flow and heat transfer of micropolar fluid through porous channel with expanding or contracting walls

The unsteady laminar incompressible flow and heat transfer characteristics of an electrically conducting micropolar fluid in a porous channel with expanding or contracting walls is investigated. the relevant partial differential equations have been reduced to ordinary ones. the reduced system of ordinary differential equations (odes) has been solved numerically by lower-upper (lu) triangular factorization or gaussian elimination and successive over relaxation (sor) method. the effects of some physical parameters such as magnetic parameter, micropolar parameters, wall expansion ratio, permeability reynolds number and prandtl number on the velocity, microrotation, temperature and the shear and couple stresses are discussed.