Abstract
An analysis has been achieved to discuss the natural convection behavior of a Newtonian fluid in a vertical semi-porous channel with varying magnetic field. The Navier-Stokes and the energy equations are reduced to a system of nonlinear PDE by using the similarity transformation. The variational iteration method (VIM) is introduced to obtain approximate solutions for velocity and temperature fields. The comparison between the analytical and numerical solutions is achieved. The analysis for the velocity and the heat transfer across the channel have been discussed for various values of the problem parameters.