Explicit representation of solutions to a linear wave equation with time delay

Fuente: arXiv
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Main Authors: Asadzade, Javad A., Gasimov, Jasarat J., Mahmudov, Nazim I., Huseynov, Ismail T.
Format: Preprint
Published: 2026
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author Asadzade, Javad A.
Gasimov, Jasarat J.
Mahmudov, Nazim I.
Huseynov, Ismail T.
author_facet Asadzade, Javad A.
Gasimov, Jasarat J.
Mahmudov, Nazim I.
Huseynov, Ismail T.
contents This paper develops an explicit spectral representation for solutions of a one-dimensional linear wave equation with a constant time delay. The model is considered on a bounded interval with non-homogeneous Dirichlet boundary data and a prescribed history function. To accommodate the loss of global smoothness in time caused by delay terms, solutions are understood in a \textit{stepwise classical sense}, allowing jump discontinuities in the second time derivative at multiples of the delay while maintaining continuity of the solution and its first time derivative. By combining separation of variables with Sturm-Liouville expansions, the delayed PDE is reduced to a family of scalar second-order delay differential equations. Using delay-dependent fundamental solutions, we derive closed-form representation formulas for the modal dynamics and reconstruct the PDE solution as a Fourier series. Convergence conditions guaranteeing uniform convergence and admissibility of termwise differentiation in space are established. A numerical example demonstrates the practical computation of truncated series solutions and their visualization.
format Preprint
id arxiv_https___arxiv_org_abs_2602_05906
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Explicit representation of solutions to a linear wave equation with time delay
Asadzade, Javad A.
Gasimov, Jasarat J.
Mahmudov, Nazim I.
Huseynov, Ismail T.
Analysis of PDEs
This paper develops an explicit spectral representation for solutions of a one-dimensional linear wave equation with a constant time delay. The model is considered on a bounded interval with non-homogeneous Dirichlet boundary data and a prescribed history function. To accommodate the loss of global smoothness in time caused by delay terms, solutions are understood in a \textit{stepwise classical sense}, allowing jump discontinuities in the second time derivative at multiples of the delay while maintaining continuity of the solution and its first time derivative. By combining separation of variables with Sturm-Liouville expansions, the delayed PDE is reduced to a family of scalar second-order delay differential equations. Using delay-dependent fundamental solutions, we derive closed-form representation formulas for the modal dynamics and reconstruct the PDE solution as a Fourier series. Convergence conditions guaranteeing uniform convergence and admissibility of termwise differentiation in space are established. A numerical example demonstrates the practical computation of truncated series solutions and their visualization.
title Explicit representation of solutions to a linear wave equation with time delay
topic Analysis of PDEs
url https://arxiv.org/abs/2602.05906