Adaptive characteristic finite element approximation of convection-diffusion optimal control problems

In this article, a characteristic finite element approximation of quadratic optimal control problems governed by linear convectiondiffusion equations is given. We derive some a posteriori error estimates for both the control and the state approximations, where the control variable is constrained by pointwise inequality. The derived error estimators are then used as an error indicator to guide the mesh refinement. In this sense, they are very important in developing adaptive finite element algorithm for the optimal control problems. Finally, a numerical example is given to validate the efficiency and reliability of the theoretical results. (c) 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013