Parametrization of subgrid scales in long-term simulations of the shallow-water equations using machine learning and convex limiting

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Hauptverfasser: Mojamder, Md Amran Hossan, Xu, Zhihang, Wang, Min, Timofeyev, Ilya
Format: Preprint
Veröffentlicht: 2026
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author Mojamder, Md Amran Hossan
Xu, Zhihang
Wang, Min
Timofeyev, Ilya
author_facet Mojamder, Md Amran Hossan
Xu, Zhihang
Wang, Min
Timofeyev, Ilya
contents We present a method for parametrizing sub-grid processes in the Shallow Water equations. We define coarse variables and local spatial averages and use a feed-forward neural network to learn sub-grid fluxes. Our method results in a local parametrization that uses a four-point computational stencil, which has several advantages over globally coupled parametrizations. We demonstrate numerically that our method improves energy balance in long-term turbulent simulations and also accurately reproduces individual solutions. The long-term simulations refer to numerical studies where a fluid flow is simulated over a duration long enough to reach a statistical steady state. The neural network parametrization can be easily combined with flux limiting to reduce oscillations near shocks. More importantly, our method provides reliable parametrizations, even in dynamical regimes that are not included in the training data.
format Preprint
id arxiv_https___arxiv_org_abs_2602_00378
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Parametrization of subgrid scales in long-term simulations of the shallow-water equations using machine learning and convex limiting
Mojamder, Md Amran Hossan
Xu, Zhihang
Wang, Min
Timofeyev, Ilya
Fluid Dynamics
Machine Learning
Atmospheric and Oceanic Physics
Computational Physics
65M99
We present a method for parametrizing sub-grid processes in the Shallow Water equations. We define coarse variables and local spatial averages and use a feed-forward neural network to learn sub-grid fluxes. Our method results in a local parametrization that uses a four-point computational stencil, which has several advantages over globally coupled parametrizations. We demonstrate numerically that our method improves energy balance in long-term turbulent simulations and also accurately reproduces individual solutions. The long-term simulations refer to numerical studies where a fluid flow is simulated over a duration long enough to reach a statistical steady state. The neural network parametrization can be easily combined with flux limiting to reduce oscillations near shocks. More importantly, our method provides reliable parametrizations, even in dynamical regimes that are not included in the training data.
title Parametrization of subgrid scales in long-term simulations of the shallow-water equations using machine learning and convex limiting
topic Fluid Dynamics
Machine Learning
Atmospheric and Oceanic Physics
Computational Physics
65M99
url https://arxiv.org/abs/2602.00378