SUPERCONVERGENT PATCH RECOVERY TECHNIQUE FOR THE FINITE-ELEMENT METHOD IN ACOUSTICS

A posteriori error estimation has become very popular, mainly in linea r elasticity. A robust implementation of the superconvergent patch rec overy technique of O. C. Zienkiewicz and J. Z. Zhu is presented for ac oustic finite element analyses: the original concepts are extended to complex variables, and both local and global behaviours of the recover y procedure and the error estimation are studied. The numerical tests confirm the improvement of the rates of convergence for the recovered solution and also show the reliability of the error estimator except a t frequencies corresponding either to the analytical or to the finite element eigenfrequencies.