用图神经微分方程预测非定常气动力,更稳定准确。
Spatio-Temporal Prediction of Unsteady Airfoil Aerodynamics Using Augmented Graph Neural Ordinary Differential Equations with Exogenous Controls

- 将图神经网络与微分方程结合,避免逐帧预测误差累积。
- 在包含跨音速激波的俯仰机翼数据上,精度提升且时序更稳定。
- 适合建模带外部输入的非线性时空系统,如飞行器气动响应。
非定常气动现象(如风浪、湍流和流固耦合)影响飞行器性能。传统计算流体力学方法(如非定常雷诺平均纳维-斯托克斯方程或线性频域法)计算成本高或依赖线性假设。机器学习方法训练后可快速计算非线性关系,适合作为代理模型。通过自回归应用图神经网络(GNN),可在离散空间域上进行时空预测。但自回归GNN存在误差累积问题,导致时间序列预测不稳定。本文提出基于图神经微分方程(GNODE)的方法,结合增广机制,实现俯仰机翼表面力的时序稳定预测。实验在含跨音速激波、瞬态行为和动态非线性的机翼模拟数据集上验证,结果表明:相比自回归基线,GNODE在时序稳定性、空间平滑性和整体精度上均有提升。通过增加隐状态维度,模型能更好捕捉历史依赖效应,增强表达能力。该方法适用于建模具有外部输入的非线性时空系统。
原文摘要 · Abstract (English)
Unsteady aerodynamic phenomena, such as gusts, turbulence, and fluid-structure interactions affect an aircraft during flight. For design, optimisation and certification, it is indispensable to quantify such unsteady aerodynamic effects. Industry-standard computational fluid dynamics methods, such as solving the unsteady Reynolds-averaged Navier-Stokes equations or the linearized frequency domain method, are either computationally expensive or restricted by assumptions like linearity. Once trained, machine learning methods are capable of computing non-linear relationships very fast, making them suitable as surrogate models. By autoregressively applying graph neural networks (GNNs), operating on a discretised spatial domain, spatio-temporal predictions can be made. However, autoregressive GNNs suffer from error accumulation leading to unstable rollouts over time. Here we show that combining GNNs with augmented Neural Ordinary Differential Equations yields temporally stable predictions of the surface forces on a pitching airfoil. We found that our approach, called GNODE, based on Graph Neural Ordinary Differential Equations, provides temporally more stable, spatially smoother, and overall more accurate results than an autoregressive GNN baseline. Tests are conducted on a dataset consisting of a simulations of a pitching airfoil, including transonic shocks, transient behaviour and dynamic non-linearities. Augmenting GNODEs with additional latent dimensions improves the expressivity and accuracy by capturing underlying history effects. The developed method demonstrates an approach that is suitable to model non-linear spatio-temporal systems with exogenous inputs.
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