Summary
Certain projection post-processing techniques have been proposed for computing the boundary flux for two-dimensional problems (e.g., see Carey, et al. [5]). In a series of numerical experiments on elliptic problems they observed that these post-processing formulas for approximate fluxes were almost (O(h 2)-accurate for linear triangular elements. In this paper we prove that the computed boundary flux isO(h 2 ln 1/h)-accurate in the maximum norm for the partial method of [5]. If the solutionuφH 3(Ω) then the boundary flux error isO(h 3/2) in theL 2-norm.
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Pehlivanov, A.I., Lazarov, R.D., Carey, G.F. et al. Superconvergence analysis of approximate boundary-flux calculations. Numer. Math. 63, 483–501 (1992). https://doi.org/10.1007/BF01385871
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DOI: https://doi.org/10.1007/BF01385871