An iterative analytic approximation for a class of nonlinear singularly perturbed parabolic partial differential equations

In this article, a closed-form iterative analytic approximation to a class of nonlinear singularly perturbed parabolic partial differential equation is developed and analysed for convergence. We have considered both parabolic reaction diffusion and parabolic convection diffusion type of problems in this paper. The solution of this class of problem is polluted by a small dissipative parameter, due to which solution often shows boundary and interior layers. A sequence of approximate analytic solution for the above class of problems is constructed using Lagrange multiplier approach. Within a general frame work, the Lagrange multiplier is optimally obtained using variational theory. The sequence of approximate analytical solutions so obtained is proved to converge the exact solution of the problem. To demonstrate the proposed method’s efficiency and accuracy, linear and nonlinear test problems have been taken into account. From numerical experiments, it is observed that the proposed method is highly accurate, straightforward.