Numerically Consistent Non-Boussinesq Subgrid-scale Stress Model with Enhanced Convergence

Fuente: arXiv
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Autores principales: Ling, Yuenong, Lozano-Durán, Adrián
Formato: Preprint
Publicado: 2026
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author Ling, Yuenong
Lozano-Durán, Adrián
author_facet Ling, Yuenong
Lozano-Durán, Adrián
contents We extend the data-assimilation approach of Ling and Lozano-Durán (AIAA 2025-1280) to develop machine-learning-based subgrid-scale stress (SGS) models for large-eddy simulation (LES) that are consistent with the numerical scheme of the flow solver. The method accounts for configurations with two inhomogeneous directions and is applied to turbulent boundary layers (TBL) under adverse pressure gradients (APG). To overcome the limitations of linear eddy-viscosity closures in complex flows, we adopt a non-Boussinesq SGS formulation along with a dissipation-matching training loss. A second improvement is the integration of a multi-task learning strategy that explicitly promotes monotonic convergence with grid refinement, a property that is often absent in conventional SGS models. A posteriori tests show that the proposed model improves predictions of the mean velocity and wall-shear stress relative to the Dynamic Smagorinsky model (DSM), while also achieving monotonic convergence with grid refinement.
format Preprint
id arxiv_https___arxiv_org_abs_2601_20265
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Numerically Consistent Non-Boussinesq Subgrid-scale Stress Model with Enhanced Convergence
Ling, Yuenong
Lozano-Durán, Adrián
Fluid Dynamics
Computational Physics
We extend the data-assimilation approach of Ling and Lozano-Durán (AIAA 2025-1280) to develop machine-learning-based subgrid-scale stress (SGS) models for large-eddy simulation (LES) that are consistent with the numerical scheme of the flow solver. The method accounts for configurations with two inhomogeneous directions and is applied to turbulent boundary layers (TBL) under adverse pressure gradients (APG). To overcome the limitations of linear eddy-viscosity closures in complex flows, we adopt a non-Boussinesq SGS formulation along with a dissipation-matching training loss. A second improvement is the integration of a multi-task learning strategy that explicitly promotes monotonic convergence with grid refinement, a property that is often absent in conventional SGS models. A posteriori tests show that the proposed model improves predictions of the mean velocity and wall-shear stress relative to the Dynamic Smagorinsky model (DSM), while also achieving monotonic convergence with grid refinement.
title Numerically Consistent Non-Boussinesq Subgrid-scale Stress Model with Enhanced Convergence
topic Fluid Dynamics
Computational Physics
url https://arxiv.org/abs/2601.20265