Hybrid Fitted Numerical Scheme for Singularly Perturbed Convection-Diffusion Problem with a Small Time Lag

In this article, a singularly perturbed convection-diffusion problem with small time lag is examined. Because of the appearance perturbation parameter, boundary layer observed in solution problem. A hybrid scheme has been constructed, which combination cubic spline method region and midpoint upwind outer on piecewise Shishkin mesh spatial direction. For discretization derivative, Crank-Nicolson used. Error analysis proposed performed. We found that second-order convergent. Numerical examples are given, numerical results agreement theoretical results. Comparisons made, give more accurate solutions higher rate convergence as compared to some previous findings available literature.