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中文核心期刊

基于数据驱动的湍流反卷积大涡模拟方法

DATA-DRIVEN DECONVOLUTION-BASED SUBGRID-SCALE MODELS FOR LARGE-EDDY SIMULATION OF TURBULENCE

  • 摘要: 大涡模拟作为模拟复杂湍流现象的关键方法, 在航空航天、燃烧推进及大气海洋等领域展现出广阔的应用价值. LES的核心在于利用亚格子应力模型表征未解析尺度对大尺度流场的非线性作用. 然而, 传统亚格子模型往往受限于单点流场信息的输入和简化的建模假设, 导致预测误差较大. 近年来, 基于数据驱动的反卷积方法为湍流封闭建模开辟了新途径. 本文综述了基于数据驱动的反卷积亚格子模型的最新进展, 重点探讨了反卷积人工神经网络模型、动态迭代近似反卷积模型、直接反卷积模型的建模思路, 并在先验与后验测试中验证模型的预测性能. 研究表明, 采用数据驱动的反卷积方法重构未滤波的原始流场状态, 再对亚格子未封闭项进行建模能够发展出高精度的亚格子模型. 新一代反卷积模型不仅在先验验证中表现出极高的精确度 (相关系数高于0.99, 相对误差低于10%), 并且在后验测试中也表现出色: 在不增加计算成本的前提下, 其对湍流统计量及瞬态涡结构的捕捉能力均显著优于动态 Smagorinsky 模型和动态混合模型等传统模型, 非常接近直接数值模拟的结果, 这表明基于数据驱动的反卷积方法能够构建高效高精度的大涡模拟亚格子模型.

     

    Abstract: Large-eddy simulation (LES), as a key method for simulating complex turbulent phenomena, has demonstrated broad application value in aerospace, combustion propulsion, and atmospheric and oceanic sciences. The core of LES is to use subgrid-scale stress (SGS) models to characterize the nonlinear effects of unresolved small-scale motions on the resolved large-scale flow field, including momentum transport and energy transfer across scales. However, traditional subgrid-scale models are often constrained by single-point flow-field inputs and simplified modeling assumptions, which limit their ability to describe complex multiscale interactions and may lead to large prediction errors. In recent years, data-driven deconvolution methods have developed a new path for turbulent closure modeling by learning or constructing inverse mappings from filtered flow variables to unresolved or unfiltered flow information. This paper reviews the latest progress in data-driven deconvolution subgrid-scale models, focusing on the modeling approaches of deconvolution artificial neural network models (DANN), dynamic iterative approximate deconvolution models (DIAD), and direct deconvolution models (DDM), and verifies their predictive performance through a priori and a posteriori tests. The research shows that reconstructing the unfiltered flow field using data-driven deconvolution methods and then modeling the subgrid-scale unclosed terms can develop highly accurate subgrid-scale models with improved representation of multiscale flow structures. The new generation of deconvolution models not only exhibits very high accuracy in a priori validation (correlation coefficients higher than 0.99, relative error lower than 10%), but also performs excellently in a posteriori tests: without increasing computational costs, its ability to capture turbulent statistics and transient vortex structures is significantly better than traditional models such as — the dynamic Smagorinsky model (DSM) and the dynamic mixed model (DMM), and is very close to the results of direct numerical simulation. These results indicate that data-driven deconvolution methods can construct efficient and highly accurate large-eddy simulation subgrid-scale models for incompressible and compressible turbulence under different filtering conditions.

     

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