The numerical solution of Helmholtz’ equation at large wavenumber is very expensive if attempted by ”traditional” discretisation methods (FDM, standard Galerkin FEM). For reliable results, the mesh has to be very fine. The bad performance of the traditional FEM for Helmholtz problems can be related to the deterioration of stability of the Helmholtz differential operator at high wavenumber. As a...

We present a new discretization method for homogeneous convectiondiffusion-reaction boundary value problems in 3D that is a non-standard finite element method with PDE-harmonic shape functions on polyhedral elements. The element stiffness matrices are constructed by means of local boundary element techniques. Our method, which we refer to as a BEM-based FEM, can therefore be considered a local ...

In this paper, we extend to the time-harmonic Maxwell equations the p–version analysis technique developed in [R. Hiptmair, A. Moiola and I. Perugia, Plane wave discontinuous Galerkin methods for the 2D Helmholtz equation: analysis of the p-version, SIAM J. Numer. Anal., 49 (2011), 264-284] for Trefftz-discontinuous Galerkin approximations of the Helmholtz problem. While error estimates in a me...

Abstract In this report, the hybrid Trefftz finite element method based on nonsingular T-complete functions is first briefly reviewed for the purpose of establishing notation; then various special purpose elements are developed to illustrat the major advantage of Trefftz methods. In HT-FEM, elements containing local defects are treated by simply replacing the regular T-complete functions with a...