Stable least-squares space-time boundary element methods for the wave equation

Journal Article (2026)
Author(s)

D. Hoonhout (TU Delft - Electrical Engineering, Mathematics and Computer Science)

R. Löscher (Graz University of Technology)

O. Steinbach (Graz University of Technology)

C. Urzúa-Torres (TU Delft - Electrical Engineering, Mathematics and Computer Science)

Research Group
Numerical Analysis
DOI related publication
https://doi.org/10.1007/s10444-026-10282-y Final published version
More Info
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Publication Year
2026
Language
English
Research Group
Numerical Analysis
Journal title
Advances in Computational Mathematics
Issue number
1
Volume number
52
Article number
7
Downloads counter
28
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Abstract

In this paper, we recast the variational formulation corresponding to the single layer boundary integral operator V for the wave equation as a minimization problem in L2(Σ), where Σ:=∂Ω×(0,T) is the lateral boundary of the space-time domain Q:=Ω×(0,T). For discretization, the minimization problem is restated as a mixed saddle point formulation. Unique solvability is established by combining conforming nested boundary element spaces for the mixed formulation such that the related bilinear form is discrete inf-sup stable. We analyze under which conditions the discrete inf-sup stability is satisfied, and moreover, we show that the mixed formulation provides a simple error indicator, which can be used for adaptivity. We present several numerical experiments showing the applicability of the method to different time-domain boundary integral formulations used in the literature.