Abstract

Wave propagation in homogeneous media is often modelled using integral equation methods. The boundary element method (BEM) is for integral equations what the finite element method is for partial differential equations. One difference is that BEM typically leads to dense discretization matrices. A major focus in the field has been the development of fast solvers for linear systems involving such dense matrices. Developments include the fast multipole method (FMM) and more algebraic methods based on the so-called H-matrix format. Yet, for time-harmonic wave propagation, these methods solve the original problem only for a single frequency. In this talk we focus on the frequency-sweeping problem: we aim to solve the scattering problem for a range of frequencies. We exploit the wavenumber-dependence of the dense discretization matrix for the 3D Helmholtz equation and demonstrate a memory-compact representation of all integral operators involved which is valid for a continuous range of frequencies, yet comes with a cost of a only small number of single frequency simulations. This is joined work at KU Leuven with Simon Dirckx, Kobe Bruyninckx and Karl Meerbergen.