The unsteady MHD free convection flow near an exponentially accelerated infinite vertical plate through porous medium with uniform heat flux in the presence of thermal radiation has been considered. The mathematical model, under the usual Boussinesq approximation, was reduced to a system of coupled linear partial differential equations for velocity and temperature. Exact solutions are obtained by the Laplace transform method. The influence of pertinent parameters such as the radiation parameter, Grashof number, Prandtl number, and time on velocity, temperature, and skin friction is shown by graphs.

The study of natural convection heat transfer from a vertical plate has received much attention in the literature due to its industrial and technological applications. Stokes [

The effects of radiation are often more important when combined with free convection. Radiation can strongly modify free convection temperature profiles. Rajesh and Varma [

We consider the unsteady free convection flow of an electrically conducting incompressible viscous fluid past an infinite vertical plate with uniform heat flux through porous medium in the presence of thermal radiation. A magnetic field of uniform strength

Then by the usual Boussinesq’s approximation, the unsteady flow is governed by the following equations:

The initial and boundary conditions are

Using (

Introducing the following non-dimensional quantities

Equation (

The corresponding skin friction, which is a measure of the shear stress at the plate, can be determined by considering (

Its dimensionless expressions are

Exact solutions for the fluid temperature and velocity are provided by (

In order to get physical insight into the problem, the obtained solutions are numerically discussed to investigate the effects of different parameters such as radiation parameter

Velocity profiles for different values of

Velocity profiles for different values of

Velocity profiles for different values of

Velocity profiles for different values of Gr.

Velocity profiles for different values of Pr.

Velocity profiles for different values of

Velocity profiles for different values of

The temperature profiles of air

Temperature profiles for different values of

Temperature profiles for different values of

Temperature profiles for different values of Pr.

The skin friction variation along time

Skin friction profiles for different values of

Skin friction profiles for different values of

Skin friction profiles for different values of

We have studied the MHD free convection flow of an incompressible viscous fluid past an exponentially accelerated vertical plate embedded in porous medium with uniform heat flux in the presence of thermal radiation. The major findings of the study are summarized as follows.

The velocity of the fluid increases due to an increase in the permeability parameter

An increase in radiation parameter

The growing values of

The temperature of the fluid increases with time

The skin friction

An increase in

The authors would like to acknowledge the Research Management Centre, UTM, for the financial support through vote numbers 4F109, 04H27 and 02H80 for this research.