Interface layers and coupling conditions for discrete kinetic models on networks: a spectral approac

Fuente: arXiv
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Main Authors: Borsche, Raul, Damm, Tobias, Klar, Axel, Zhou, Yizhou
Format: Preprint
Published: 2025
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author Borsche, Raul
Damm, Tobias
Klar, Axel
Zhou, Yizhou
author_facet Borsche, Raul
Damm, Tobias
Klar, Axel
Zhou, Yizhou
contents We consider kinetic and related macroscopic equations on networks. A class of linear kinetic BGK models is considered, where the limit equation for small Knudsen numbers is given by the wave equation. Coupling conditions for the macroscopic equations are obtained from the kinetic coupling conditions via an asymptotic analysis near the nodes of the network and the consideration of coupled solutions of kinetic half-space problems. Analytical results are obtained for a discrete velocity version of the coupled half-space problems. Moreover, an efficient spectral method is developed to solve the coupled discrete velocity half-space problems. In particular, this allows to determine the relevant coefficients in the coupling conditions for the macroscopic equations from the underlying kinetic network problem. These coefficients correspond to the so-called extrapolation length for kinetic boundary value problems. Numerical results show the accuracy and fast convergence of the approach. Moreover, a comparison of the kinetic solution on the network with the macroscopic solution is presented.
format Preprint
id arxiv_https___arxiv_org_abs_2512_04634
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Interface layers and coupling conditions for discrete kinetic models on networks: a spectral approac
Borsche, Raul
Damm, Tobias
Klar, Axel
Zhou, Yizhou
Numerical Analysis
82B40, 90B10, 65M08
We consider kinetic and related macroscopic equations on networks. A class of linear kinetic BGK models is considered, where the limit equation for small Knudsen numbers is given by the wave equation. Coupling conditions for the macroscopic equations are obtained from the kinetic coupling conditions via an asymptotic analysis near the nodes of the network and the consideration of coupled solutions of kinetic half-space problems. Analytical results are obtained for a discrete velocity version of the coupled half-space problems. Moreover, an efficient spectral method is developed to solve the coupled discrete velocity half-space problems. In particular, this allows to determine the relevant coefficients in the coupling conditions for the macroscopic equations from the underlying kinetic network problem. These coefficients correspond to the so-called extrapolation length for kinetic boundary value problems. Numerical results show the accuracy and fast convergence of the approach. Moreover, a comparison of the kinetic solution on the network with the macroscopic solution is presented.
title Interface layers and coupling conditions for discrete kinetic models on networks: a spectral approac
topic Numerical Analysis
82B40, 90B10, 65M08
url https://arxiv.org/abs/2512.04634