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Bayesian conditional diffusion models for versatile spatiotemporal turbulence generation

delete2024-07-01
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OA
AI
H
Han Gao
X
Xu Han
X
Xiantao Fan
L
Luning Sun
L
Liu, Li -Ping
L
Lian Duan
J
Jianxun Wang *
DOI:10.1016/j.cma.2024.117023delete
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Abstract

Abstract

En 中文
Turbulent flows, characterized by their chaotic and stochastic nature, have historically presented formidable challenges to predictive computational modeling. Traditional eddy -resolved numerical simulations often require vast computational resources, making them impractical or infeasible for numerous engineering applications. As an alternative, deep learning -based surrogate models have emerged, offering data -drive solutions. However, these are typically constructed within deterministic settings, leading to shortfall in capturing the innate chaotic and stochastic behaviors of turbulent dynamics. In this study, we introduce a novel generative framework grounded in probabilistic diffusion models for versatile generation of spatiotemporal turbulence under various conditions. Our method unifies both unconditional and conditional sampling strategies within a Bayesian framework, which can accommodate diverse conditioning scenarios, including those with a direct differentiable link between specified conditions and generated unsteady flow outcomes, as well as scenarios lacking such explicit correlations. A notable feature of our approach is the method proposed for long -span flow sequence generation, which is based on autoregressive gradient -based conditional sampling, eliminating the need for cumbersome retraining processes. We evaluate and showcase the versatile turbulence generation capability of our framework through a suite of numerical experiments, including: (1) the synthesis of Large Eddy Simulations (LES) simulated instantaneous flow sequences from unsteady Reynolds -Averaged Navier-Stokes (URANS) inputs; (2) holistic generation of inhomogeneous, anisotropic wall -bounded turbulence, whether from given initial conditions, prescribed turbulence statistics, or entirely from scratch; (3) super -resolved generation of high-speed turbulent boundary layer flows from low -resolution data across a range of input resolutions. Collectively, our numerical experiments highlight the merit and transformative potential of the proposed methods, making a significant advance in the field of turbulence generation.
Keywords:
Turbulent flow
Generative modeling
Bayesian statistics
Surrogate modeling
Wall-bounded turbulence
Chaotic dynamics
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Journal

Computer Methods in Applied Mechanics and Engineering cover
Computer Methods in Applied Mechanics and Engineering
IF:
7.3
Papers:
1.3W
Citations:
5.6W

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H
Harvard University
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T
tufts university
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University of Notre Dame
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U
united states department of energy (doe)
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11.3W
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