arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.02762physics.flu-dyncs.LGphysics.comp-ph
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用于turbulence低阶模型时间预测的循环神经网络和基于Koopman的框架

Recurrent neural networks and Koopman-based frameworks for temporal predictions in a low-order model of turbulence

University of Tehran(德黑兰大学);KTH Royal Institute of Technology(瑞典皇家理工学院);Swedish e-Science Research Centre (SeRC)(瑞典e-Science研究中心)

Hamidreza Eivazi, Luca Guastoni, Philipp Schlatter, Hossein Azizpour, Ricardo Vinuesa

摘要:

Moehlis等人(New J. Phys. 6,56,2004)在预测近壁湍流低阶模型的时间动力学中评估了循环神经网络和基于Koopman的框架的能力。我们的研究结果表明,有可能获得良好的长期统计和混沌系统的动态行为的再现与适当训练的长短期记忆(LSTM)网络,导致相对误差的平均值和波动低于$1\%$。此外,一个新开发的基于Koopman的框架,称为Koopman与非线性强迫(KNF),导致相同水平的准确性的统计数据在一个显着降低计算费用。此外,KNF框架在短期预测方面优于LSTM网络。我们还观察到,使用的损失函数的基础上的混沌系统的瞬时预测可以导致次优再现长期统计。因此,我们提出了一个模型选择标准的基础上计算的统计,它允许实现良好的统计重建,即使在小的数据集,在瞬时预测的准确性损失最小。

英文摘要:

The capabilities of recurrent neural networks and Koopman-based frameworks are assessed in the prediction of temporal dynamics of the low-order model of near-wall turbulence by Moehlis et al. (New J. Phys. 6, 56, 2004). Our results show that it is possible to obtain excellent reproductions of the long-term statistics and the dynamic behavior of the chaotic system with properly trained long-short-term memory (LSTM) networks, leading to relative errors in the mean and the fluctuations below $1\%$. Besides, a newly developed Koopman-based framework, called Koopman with nonlinear forcing (KNF), leads to the same level of accuracy in the statistics at a significantly lower computational expense. Furthermore, the KNF framework outperforms the LSTM network when it comes to short-term predictions. We also observe that using a loss function based only on the instantaneous predictions of the chaotic system can lead to suboptimal reproductions in terms of long-term statistics. Thus, we propose a model-selection criterion based on the computed statistics which allows to achieve excellent statistical reconstruction even on small datasets, with minimal loss of accuracy in the instantaneous predictions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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