Solving complex flow, heat and mass transfer problems numerically created a new branch of fluid dynamics: CFD. In this paper it is inferred that it might not always be the best strategy to simply delegate the problem to the computer. Instead it is suggested to combine CFD and asymptotic methods as a powerful tool: ACFD i.e. asymptotic computational fluid dynamics. A general four step procedure is outlined. The method is illustrated for the simple Couette flow under various heat and mass transfer conditions with references to problems of higher complexity at the end of each chapter.