Higher-order gradient post-processings for second-order elliptic problems Original Research Article

Global, element-by-element and macroelement post-processing recovery techniques based on least-square residuals of equilibrium equation and irrotationality condition are proposed for second-order elliptic problems. Improved accuracy for the flux finite element approximations is obtained with low computational cost and easy implementation. Error estimates are derived and numerical experiments are reported confirming the higher-order rates of convergence predicted in the analysis.