“…One other objective is also to implement a multilevel adaptive algorithm for enrichments using the gradient of the solution as an error indicator. Automatic adaptation is an useful tool to improve the accuracy and efficiency of the numerical solution and various adaptation techniques have been used for convection-diffusion problems which can be generally categorized as methods based on error estimates or methods based on physical features such as gradients, see for example [20,21,3,22]. This second approach is the most popular strategy of evaluating error behavior and it is adopted in the present work.…”