Convergence Analysis for Finite Element Discretizations
of Highly Indefinite Helmholtz Problems
Stefan Sauter
University of Zurich, visiting UCSD
Abstract:
A rigorous convergence theory for Galerkin methods for a model
Helmholtz problem in R^{d}, d=1,2,3, is presented.
General conditions on the approximation properties of the
approximation space are stated that ensure quasi-optimality
of the method. As an application of the general theory,
a full error analysis of the classical hp-version
of the finite element method (hp-FEM) is presented
where the dependence on the mesh width h, the
approximation order p, and the wave number k is
given explicitly. In particular, it is shown that
quasi-optimality is obtained under the conditions
that kh/p is sufficiently small and the polynomial
degree p is at least O(log k). This result improves existing
stability conditions substantially.