Hybrid Fourier Neural Operator-Lattice Boltzmann Method

Fuente: arXiv
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Autores principales: Junk, Alexandra, Winter, Josef M., Tütken, Meike, Schmidt, Steffen, Adams, Nikolaus A.
Formato: Preprint
Publicado: 2026
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author Junk, Alexandra
Winter, Josef M.
Tütken, Meike
Schmidt, Steffen
Adams, Nikolaus A.
author_facet Junk, Alexandra
Winter, Josef M.
Tütken, Meike
Schmidt, Steffen
Adams, Nikolaus A.
contents We propose an accelerated computational fluid dynamics framework based on a hybrid Fourier Neural Operator-Lattice Boltzmann Method (FNO-LBM) for steady and unsteady weakly compressible flows. FNO-based initialization significantly accelerates LBM in reaching steady-states of porous media flows across all macroscopic fields, achieving up to 70% speed-up in convergence of density and more than 40% of pressure-drop while preserving the final steady-state accuracy. Simulations of unsteady flows can be accelerated by hybrid coupling strategies that employ FNO rollouts embedded into LBM time advancement in a way of super-time-stepping. Global and time-resolved error metrics across 100 trajectories for generic 2D flows demonstrate that hybridization consistently improves accuracy and stabilizes long-horizon rollouts. Best efficiency is achieved for a lightweight 2.6M-parameter FNO, which diverges under pure autoregressive rollout but achieves 96-99.8% error reduction under hybrid coupling, matching the predictive capability of a much more expensive 11.2M-parameter model. The hybrid framework enhances predictive fidelity, suppresses error accumulation, and enables small and cheap surrogate models to operate effectively within the same error regime as larger surrogates. These results demonstrate that hybrid neural-operator coupling achieves robust and computationally efficient accelerated LBM while maintaining physically consistent flow evolution.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27158
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Hybrid Fourier Neural Operator-Lattice Boltzmann Method
Junk, Alexandra
Winter, Josef M.
Tütken, Meike
Schmidt, Steffen
Adams, Nikolaus A.
Fluid Dynamics
We propose an accelerated computational fluid dynamics framework based on a hybrid Fourier Neural Operator-Lattice Boltzmann Method (FNO-LBM) for steady and unsteady weakly compressible flows. FNO-based initialization significantly accelerates LBM in reaching steady-states of porous media flows across all macroscopic fields, achieving up to 70% speed-up in convergence of density and more than 40% of pressure-drop while preserving the final steady-state accuracy. Simulations of unsteady flows can be accelerated by hybrid coupling strategies that employ FNO rollouts embedded into LBM time advancement in a way of super-time-stepping. Global and time-resolved error metrics across 100 trajectories for generic 2D flows demonstrate that hybridization consistently improves accuracy and stabilizes long-horizon rollouts. Best efficiency is achieved for a lightweight 2.6M-parameter FNO, which diverges under pure autoregressive rollout but achieves 96-99.8% error reduction under hybrid coupling, matching the predictive capability of a much more expensive 11.2M-parameter model. The hybrid framework enhances predictive fidelity, suppresses error accumulation, and enables small and cheap surrogate models to operate effectively within the same error regime as larger surrogates. These results demonstrate that hybrid neural-operator coupling achieves robust and computationally efficient accelerated LBM while maintaining physically consistent flow evolution.
title Hybrid Fourier Neural Operator-Lattice Boltzmann Method
topic Fluid Dynamics
url https://arxiv.org/abs/2604.27158