Thin-film flow of MHD third grade fluid in a porous space

The main aim of this paper is to compare the solutions of the traditional perturbation method, homotopy perturbation method (HPM), and homotopy analysis method (HAM). An illustrative example for thin-film flow of magnetohydrodynamic (MHD) third grade fluid on a moving belt is considered in a porous medium. First, it has been shown explicitly that, like the traditional perturbation method, HPM is also valid only for weak nonlinearity. Second, it has been shown that this deficiency can be completely controlled using HAM. Finally, the results are discussed under the influence of pertinent parameters.