Abstract
The main aim of this work is to present a new reliable approach to compute an approximate solution of the system of nonlinear differential equations governing the problem of two-dimensional and axisymmetric unsteady flows due to normally expanding or contracting parallel plates by the homotopy perturbation method, and the Sumudu transform is adopted in the solution procedure. The method finds the solution without any discretization or restrictive assumptions and avoids the roundoff errors. The numerical solutions obtained by the proposed technique indicate that the approach is easy to implement and computationally very attractive.