[HTML][HTML] The Helmholtz equation in heterogeneous media: a priori bounds, well-posedness, and resonances

IG Graham, OR Pembery, EA Spence - Journal of Differential Equations, 2019 - Elsevier
We consider the exterior Dirichlet problem for the heterogeneous Helmholtz equation, ie the
equation∇⋅(A∇ u)+ k 2 nu=− f where both A and n are functions of position. We prove new …

For Most Frequencies, Strong Trapping Has a Weak Effect in Frequency‐Domain Scattering

D Lafontaine, EA Spence… - Communications on Pure …, 2021 - Wiley Online Library
It is well‐known that when the geometry and/or coefficients allow stable trapped rays, the
outgoing solution operator of the Helmholtz equation grows exponentially through a …

Optimal constants in nontrapping resolvent estimates and applications in numerical analysis

J Galkowski, EA Spence, J Wunsch - Pure and Applied Analysis, 2019 - msp.org
We study the resolvent for nontrapping obstacles on manifolds with Euclidean ends. It is well
known that for such manifolds the outgoing resolvent satisfies∥ χ R (k) χ∥ L 2→ L 2≤ C k …

A new heterogeneous multiscale method for the Helmholtz equation with high contrast

M Ohlberger, B Verfurth - Multiscale Modeling & Simulation, 2018 - SIAM
In this paper, we suggest a new heterogeneous multiscale method (HMM) for the Helmholtz
equation with high contrast. The method is constructed for a setting as in Bouchitte and …

Wavenumber-explicit stability and convergence analysis of hp finite element discretizations of Helmholtz problems in piecewise smooth media

M Bernkopf, T Chaumont-Frelet, JM Melenk - arXiv preprint arXiv …, 2022 - arxiv.org
We present a wavenumber-explicit convergence analysis of the hp finite element method
applied to a class of heterogeneous Helmholtz problems with piecewise analytic coefficients …

Exponentially convergent multiscale methods for 2D high frequency heterogeneous Helmholtz equations

Y Chen, TY Hou, Y Wang - Multiscale Modeling & Simulation, 2023 - SIAM
In this paper, we present a multiscale framework for solving the Helmholtz equation in
heterogeneous media without scale separation and in the high frequency regime where the …

Domain decomposition preconditioners for high-order discretizations of the heterogeneous Helmholtz equation

S Gong, IG Graham, EA Spence - IMA Journal of Numerical …, 2021 - academic.oup.com
We consider one-level additive Schwarz domain decomposition preconditioners for the
Helmholtz equation with variable coefficients (modelling wave propagation in …

Decompositions of high-frequency Helmholtz solutions via functional calculus, and application to the finite element method

J Galkowski, D Lafontaine, EA Spence… - SIAM Journal on …, 2023 - SIAM
Over the last 10 years, results from [JM Melenk and S. Sauter, Math. Comp., 79 (2010), pp.
1871–1914],[JM Melenk and S. Sauter, SIAM J. Numer. Anal., 49 (2011), pp. 1210–1243],[S …

Computational high frequency scattering from high-contrast heterogeneous media

D Peterseim, B Verfürth - Mathematics of Computation, 2020 - ams.org
This article considers the computational (acoustic) wave propagation in strongly
heterogeneous structures beyond the assumption of periodicity. A high contrast between the …

Stability estimate for the Helmholtz equation with rapidly jumping coefficients

S Sauter, C Torres - Zeitschrift für angewandte Mathematik und Physik, 2018 - Springer
The goal of this paper is to investigate the stability of the Helmholtz equation in the high-
frequency regime with non-smooth and rapidly oscillating coefficients on bounded domains …