arXiv:2512.19031cs.LG2025-12

用代理模型加速物理模型训练,降低千万级仿真的计算成本。

A Surrogate-Augmented Symbolic CFD-Driven Training Framework for Accelerating Multi-objective Physical Model Development

  • 用代理模型预判机器学习生成模型的误差,仅对高潜力模型做完整仿真。
  • 在多目标优化中实现自适应权重,提升复杂流动场景下的建模效率。
  • 适用于流体模拟中的复杂物理模型开发,尤其适合算力受限的研究者。

基于计算流体力学(CFD)的机器学习训练框架通过将候选模型嵌入CFD求解器并对比参考数据来构建物理一致的湍流模型,但每次评估需数百至数千次高保真仿真,导致复杂流动问题计算成本过高。为此,本文提出一种融合代理建模的符号化CFD驱动训练框架,在实时训练中引入代理模型,通过历史仿真数据学习模型误差分布,并持续迭代优化。新生成的模型先由代理模型评估,仅预测误差小或不确定性高的模型才进行全量CFD仿真。符号回归生成的离散表达式通过平均输入符号值映射到连续空间,输入概率型代理模型。为支持多目标训练,代理模型扩展为多输出形式,核函数推广为矩阵形式,对每个目标提供均值与方差预测。基于这些概率输出设计选择指标,以确定最优训练配置。该框架在统计一维和二维流动场景中进行了验证,涵盖单表达式与多表达式模型优化。所有案例均显著降低训练成本,同时保持与原始方法相当的预测精度。

原文摘要 · Abstract (English)

Computational Fluid Dynamics (CFD)-driven training combines machine learning (ML) with CFD solvers to develop physically consistent closure models with improved predictive accuracy. In the original framework, each ML-generated candidate model is embedded in a CFD solver and evaluated against reference data, requiring hundreds to thousands of high-fidelity simulations and resulting in prohibitive computational cost for complex flows. To overcome this limitation, we propose an extended framework that integrates surrogate modeling into symbolic CFD-driven training in real time to reduce training cost. The surrogate model learns to approximate the errors of ML-generated models based on previous CFD evaluations and is continuously refined during training. Newly generated models are first assessed using the surrogate, and only those predicted to yield small errors or high uncertainty are subsequently evaluated with full CFD simulations. Discrete expressions generated by symbolic regression are mapped into a continuous space using averaged input-symbol values as inputs to a probabilistic surrogate model. To support multi-objective model training, particularly when fixed weighting of competing quantities is challenging, the surrogate is extended to a multi-output formulation by generalizing the kernel to a matrix form, providing one mean and variance prediction per training objective. Selection metrics based on these probabilistic outputs are used to identify an optimal training setup. The proposed surrogate-augmented CFD-driven training framework is demonstrated across a range of statistically one- and two-dimensional flows, including both single- and multi-expression model optimization. In all cases, the framework substantially reduces training cost while maintaining predictive accuracy comparable to that of the original CFD-driven approach.

CFD代理模型符号回归多目标优化

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