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The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method (OHAM) and fourth order Runge-Kutta numerical method. Comparison between OHAM and numerical method shows that OHAM is an exact and high efficient method for solving these kinds of problems. The results are presented to study the velocity and rotation profiles for different physical parameters such as Reynolds number, vortex viscosity parameter, spin gradient viscosity and microinertia density parameter. As an important outcome, the magnitude of the microrotation increases with an increase in the values of injection velocity while it decreases by increasing the values of suction velocity.

In this paper, steady, laminar, incompressible, and two-dimensional micropolar flow between a porous disk and a nonporous disk is considered. By introducing suitable similarity transformations, the problem is reduced to a set of nonlinear boundary value problems. Optimal homotopy asymptotic method is employed to obtain the series solutions for velocity and microrotation distribution. The accuracy of results is examined by the fourth-order Runge-Kutta numerical method. The results are presented to study the velocity and rotation profiles for different physical parameters such as: Reynolds number, vortex viscosity parameter, spin gradient viscosity, and microinertia density parameter. As a result, the magnitude of the injection velocity has strong influence on the flow velocities and the microrotation.

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In this study, effect of mass transfer on laminar flow of viscoelastic fluid in a porous channel with high permeability medium is investigated. The viscoelastic model used in this work is the upper convected Maxwell (UCM) model. Applying the similarity transformation, the governing partial equations are converted to ordinary differential equations. The problem is studied by a hybrid technique based on Differential Transformation Method (DTM) and iterative Newton's method (INM). Also a numerical solution is done to validate the present analytical method. The effects of active parameters such as Darcy number (Da), transpiration Reynolds number (Re T ) Deborah number (De) and Schmidt number (Sc) on the both velocity components and concentration function are discussed in this work. The results indicate that the stream function increases for large Deborah and Darcy numbers. The axial velocity is initially decreased by increasing the Deborah number but then increased while approaching the upper channel wall.ª 2014 Production and hosting by Elsevier B.V. on behalf