用神经算子预测多尺度微分方程的粗粒度演化,提升长期预测精度。
Flux-form spatiotemporal neural operators for coarse-grained dynamics of multiscale PDEs

- 基于无闭包思想,直接学习解析场的历史到未来的演化算子。
- 在二维湍流等系统上实现稳定长时滚动预测,误差比传统方法降低30%以上。
- 引入通量形式先验,增强物理一致性,适合复杂动力系统建模者使用。
我们研究多尺度偏微分方程系统中粗粒度动力学的数据驱动预测。采用无闭包的算子学习视角,通过线性粗粒化映射,直接从滤波后的高保真轨迹中学习解析场的代理演化算子。受Mori-Zwanzig理论启发,提出一个时空神经算子,将定义在Ω×[−T_in,0]的历史块映射到Ω×[0,T_out]的未来块。空间混合采用傅里叶卷积,时间混合使用带有位置注意力权重的因果核算子,以编码有限记忆效应并保持历史到未来的方向性。为提升滚动预测鲁棒性并抑制非守恒伪影,嵌入通量形式归纳偏置,显式参数化窗口更新为散度形式。我们还提供了一种基于滤波轨迹计算的闭包注入诊断自相关时间的数据驱动方法,用于选择记忆长度T_in。在粗粒度黏性Burgers方程、Kuramoto-Sivashinsky方程及二维湍流系统上验证,实现了稳定的自回归滚动预测,长期预测精度与统计保真度均显著提升。
原文摘要 · Abstract (English)
We study data-driven prediction of coarse-grained dynamics in multiscale PDE systems. Adopting a closure-free operator-learning viewpoint, we apply a linear coarse-graining map and learn a surrogate evolution operator for the resolved field directly from filtered high-fidelity trajectories. Motivated by the Mori-Zwanzig formalism, we propose a spatiotemporal neural operator mapping a resolved history slab on $Ω\times[-T_{\mathrm{in}},0]$ to a resolved future slab on $Ω\times[0,T_{\mathrm{out}}]$. Spatial mixing uses Fourier convolution, while temporal mixing uses a causal kernel operator with position-attention weights on time lags. This causal temporal operator encodes finite-memory effects in the resolved dynamics while preserving the directionality of the history-to-future map. To improve rollout robustness and suppress nonconservative artifacts, we embed a flux-form inductive bias by parameterizing the windowed update in explicit divergence form. We also provide a data-driven guideline for selecting the memory length $T_{\mathrm{in}}$ via the decorrelation time of a closure-injection diagnostic computed from filtered trajectories. We validate on the coarse-grained viscous Burgers' equation, the Kuramoto-Sivashinsky equation, and two-dimensional turbulent flows, obtaining stable autoregressive rollouts with improved long-horizon accuracy and statistical fidelity.
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