论文标题

神经涡流法:从有限拉格朗日颗粒到无限的尺寸欧拉动力学

Neural Vortex Method: from Finite Lagrangian Particles to Infinite Dimensional Eulerian Dynamics

论文作者

Xiong, Shiying, He, Xingzhe, Tong, Yunjin, Deng, Yitong, Zhu, Bo

论文摘要

在流体数值分析的领域中,存在一个长期存在的问题:缺少严格的数学工具来从连续流场绘制到离散的涡流粒子,从而使拉格朗日粒子无法继承大规模的Eulerian求解器的高分辨率。为了应对这一挑战,我们提出了一种基于学习的新框架神经涡流方法(NVM),该框架对拉格朗日涡流结构及其相互作用动态构建了神经网络描述,以物理精确的方式重建高分辨率的欧拉流动场。我们的基础架构的关键组成部分由两个网络组成:一个涡流表示网络,可从基于网格的速度字段和涡流相​​互作用网络中识别拉格朗日涡流,以了解这些有限结构的基础管理动力学。通过将这两个网络嵌入涡度到速度泊松求解器并使用从高分辨率直接数值模拟获得的高保真数据训练其参数,我们可以在所有先前的常规涡流方法(CVMS)上预测准确的流体动力学。据我们所知,我们的方法是第一种可以利用有限粒子运动来学习无限尺寸动态系统的方法。我们证明了我们方法在产生高度准确的预测结果的功效,其计算成本低,跨越涡流环系统,湍流系统以及由具有不同外力的Euler方程控制的系统。

In the field of fluid numerical analysis, there has been a long-standing problem: lacking of a rigorous mathematical tool to map from a continuous flow field to discrete vortex particles, hurdling the Lagrangian particles from inheriting the high resolution of a large-scale Eulerian solver. To tackle this challenge, we propose a novel learning-based framework, the Neural Vortex Method (NVM), which builds a neural-network description of the Lagrangian vortex structures and their interaction dynamics to reconstruct the high-resolution Eulerian flow field in a physically-precise manner. The key components of our infrastructure consist of two networks: a vortex representation network to identify the Lagrangian vortices from a grid-based velocity field and a vortex interaction network to learn the underlying governing dynamics of these finite structures. By embedding these two networks with a vorticity-to-velocity Poisson solver and training its parameters using the high-fidelity data obtained from high-resolution direct numerical simulation, we can predict the accurate fluid dynamics on a precision level that was infeasible for all the previous conventional vortex methods (CVMs). To the best of our knowledge, our method is the first approach that can utilize motions of finite particles to learn infinite dimensional dynamic systems. We demonstrate the efficacy of our method in generating highly accurate prediction results, with low computational cost, of the leapfrogging vortex rings system, the turbulence system, and the systems governed by Euler equations with different external forces.

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