The Optimal Error Estimate of Streamline Diffusion Finite Element Method for Convection-diffusion Problem

In this paper, we consider the streamline diffusion finite element method (SDFEM) with bilinear element for convection dominated diffusion problems. In the previous literature, under the condition of e≤h~2, the optimal error estimate in L~2 is derived for SDFEM scheme. However, in this paper, we'll improve the condition e≤h~2 as e≤h and use a different method to prove the optimal error estimate in L~2 for SDFEM scheme.