Use of optimal homotopy asymptotic method and galerkin's finite element formulation in the study of heat transfer flow of a third grade fluid between parallel plates

We investigate the effectiveness of the optimal homotopy asymptotic method (OHAM) in solving nonlinear systems of differential equations. In particular we consider the heat transfer flow of a third grade fluid between two heated parallel plates separated by a finite distance. The method is successfully applied to study the constant viscosity models, namely plane Couette flow, plane Poiseuille flow, and plane Couette-Poiseuille flow for velocity fields and the temperature distributions. Numerical solutions of the systems are also obtained using a finite element method (FEM). A comparative analysis between the semianalytical solutions of OHAM and numerical solutions by FEM are presented. The semianalytical results are found to be in good agreement with numerical solutions. The results reveal that the OHAM is precise, effective, and easy to use for such systems of nonlinear differential equations.