The present paper deals with the study of unsteady heat and mass transfer characteristics of a viscous incompressible electrically conducting micropolar fluid. The flow past over a stretching sheet through a porous medium in the presence of viscous dissipation. A uniform magnetic field is applied transversely to the direction of the flow. Similarity transformations are used to convert the governing time dependent non-linear boundary layer equations into a system of non-linear ordinary differential equations that are solved numerically by Runge–Kutta fourth order method with a shooting technique. The influence of unsteady parameter (A), Eckert number (Ec), porous parameter (Kp), Prandtl number (Pr), Schmidt number (Sc) on velocity, temperature and concentration profiles are shown graphically. The buoyancy force retards the fluid near the velocity boundary layer in case of opposing flow and is favorable for assisting flow. In case of assisting flow, the absence of porous matrix enhances the flow. The impact of physical parameters on skin friction co-efficient, wall couple stress and the local Nusselt number and Sherwood number are shown in tabular form

An attempt has been made to study a steady planar flow of an electrically conducting incompressible viscous fluid on a vertical plate with variable wall temperature and concentration in a doubly stratified micropolar fluid in the presence of a transverse magnetic field. The novelty of the present study is to account for the effect of a spanwise variable volumetric heat source in a thermal and solutal stratified medium. The coupled non-linear governing equations are solved numerically by using Runge–Kutta fourth order with shooting technique. The flow characteristics in boundary layers along with bounding surface are presented and analyzed with the help of graphs

An attempt has been made to study the heat and mass transfer effect in a boundary layer flow of an electrically conducting viscous fluid subject to transverse magnetic field past over a moving vertical plate through porous medium in the presence of heat source and chemical reaction. The governing non-linear partial differential equations have been transformed into a two-point boundary value problem using similarity variables and then solved numerically by fourth order Runge–Kutta fourth order method with shooting technique. Graphical results are discussed for non-dimensional velocity, temperature and concentration profiles while numerical values of the skin friction, Nusselt number and Sherwood number are presented in tabular form for various values of parameters controlling the flow system

In this paper it is intended to analyse entropy generation by applying second law of thermodynamics to magnetohydrodynamic flow, heat and mass transfer of an electrically conducting viscoelastic liquid (Walters B′) past on a stretching surface, taking into account the effects of Joule dissipation, viscous dissipation and Darcy dissipation, and internal heat generation. The boundary layer equations are solved analytically by using Kummer’s function. The entropy generation has been computed considering Darcy dissipation besides viscous and Joule dissipation. Results for some special cases of the present analysis are in good agreement with the existing literature. Increase in viscoelastic and magnetic parameter reduces the velocity. Increase in elastic parameter causes a greater retardation in the velocity. Presence of porous matrix enhances temperature whereas increase in Prandtl number decreases the temperature. One striking result of the present study is that Darcy dissipation favours higher level entropy generation in all the cases except the flow of liquid with low thermal diffusivity assuming the process to be irreversible