A Bi-fidelity numerical method for velocity discretization of Boltzmann equations

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Hauptverfasser: Crouseilles, Nicolas, Hao, Zhen, Liu, Liu
Format: Preprint
Veröffentlicht: 2025
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author Crouseilles, Nicolas
Hao, Zhen
Liu, Liu
author_facet Crouseilles, Nicolas
Hao, Zhen
Liu, Liu
contents In this paper, we introduce a bi-fidelity algorithm for velocity discretization of Boltzmann-type kinetic equations under multiple scales. The proposed method employs a simpler and computationally cheaper low-fidelity model to capture a small set of significant velocity points through the greedy approach, then evaluates the high-fidelity model only at these few velocity points and to reconstruct a bi-fidelity surrogate. This novel method integrates a simpler collision term of relaxation type in the low-fidelity model and an asymptotic-preserving scheme in the high-fidelity update step. Both linear Boltzmann under diffusive scaling and the nonlinear full Boltzmann in hyperbolic scaling are discussed. We show the weak asymptotic-preserving property and empirical error bound estimates. Extensive numerical experiments on linear semiconductor and nonlinear Boltzmann problems with smooth or discontinuous initial conditions and under various regimes have been carefully studied, which demonstrates the effectiveness and robustness of our proposed scheme.
format Preprint
id arxiv_https___arxiv_org_abs_2507_19945
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Bi-fidelity numerical method for velocity discretization of Boltzmann equations
Crouseilles, Nicolas
Hao, Zhen
Liu, Liu
Numerical Analysis
In this paper, we introduce a bi-fidelity algorithm for velocity discretization of Boltzmann-type kinetic equations under multiple scales. The proposed method employs a simpler and computationally cheaper low-fidelity model to capture a small set of significant velocity points through the greedy approach, then evaluates the high-fidelity model only at these few velocity points and to reconstruct a bi-fidelity surrogate. This novel method integrates a simpler collision term of relaxation type in the low-fidelity model and an asymptotic-preserving scheme in the high-fidelity update step. Both linear Boltzmann under diffusive scaling and the nonlinear full Boltzmann in hyperbolic scaling are discussed. We show the weak asymptotic-preserving property and empirical error bound estimates. Extensive numerical experiments on linear semiconductor and nonlinear Boltzmann problems with smooth or discontinuous initial conditions and under various regimes have been carefully studied, which demonstrates the effectiveness and robustness of our proposed scheme.
title A Bi-fidelity numerical method for velocity discretization of Boltzmann equations
topic Numerical Analysis
url https://arxiv.org/abs/2507.19945