An ESFEM for analyzing threedimensional acoustic problems

Itiswell-knownthatonekeyissueofsolvingtheHelmholtzequationusingfiniteelementmethod(FEM)istheaccuracydeteriorationinthesolutionwithincreasingwavenumberduetothe‘‘numericaldispersionerror”.Suchanumericaldispersionerrorisessentiallycausedbythe‘‘overly-stiff”na