论文标题
神经粒子方法 - 更新的Lagrangian物理学知情了计算流体动力学的神经网络
The Neural Particle Method -- An Updated Lagrangian Physics Informed Neural Network for Computational Fluid Dynamics
论文作者
论文摘要
数值模拟在工业设计过程中是必不可少的。它可以取代昂贵的实验,甚至减少对原型的需求。虽然借助数值模拟设计的产品经历了连续的改进,但对于数值模拟本身也必须是正确的。最新的是,没有通用数值方法可用,可以准确解决从流体到固体力学的各种物理学,包括大变形和自由表面流动现象。这些复杂的多物理问题例如在增材制造过程中发生。从这个意义上讲,机器学习的最新发展显示了数值模拟的希望。最近已经显示,与标准数值方法中的方程式系统相比,可以仅基于初始和边界条件来训练神经网络。神经网络是平滑的,可区分的功能,可以用作部分偏微分方程(PDE)的全局ANSATZ。尽管这个想法可以追溯到20年前[Lagaris等,1998],但直到最近才开发出一种用于时间依赖问题的方法[Raissi等,2019]。在后者的情况下,已经构建了具有前所未有的高阶的隐式runge kutta方案来求解标量值的PDE。我们以上述工作为基础,以开发一种更新的拉格朗日方法,以解决不可压缩的自由表面流量,但受到无粘性Euler方程的影响。该方法易于实施,并且不需要任何特定的算法处理,这些算法通常是准确解决不可压缩性约束所必需的。由于其无网状特征,我们将其命名为神经粒子方法(NPM)。即使离散点的位置高度不规则,也将证明NPM保持稳定和准确。
Numerical simulation is indispensable in industrial design processes. It can replace expensive experiments and even reduce the need for prototypes. While products designed with the aid of numerical simulation undergo continuous improvement, this must also be true for numerical simulation itself. Up to date, no general purpose numerical method is available which can accurately resolve a variety of physics ranging from fluid to solid mechanics including large deformations and free surface flow phenomena. These complex multi-physics problems occur for example in Additive Manufacturing processes. In this sense, the recent developments in Machine Learning display promise for numerical simulation. It has recently been shown that instead of solving a system of equations as in standard numerical methods, a neural network can be trained solely based on initial and boundary conditions. Neural networks are smooth, differentiable functions that can be used as a global ansatz for Partial Differential Equations (PDEs). While this idea dates back to more than 20 years ago [Lagaris et al., 1998], it is only recently that an approach for the solution of time dependent problems has been developed [Raissi et al., 2019]. With the latter, implicit Runge Kutta schemes with unprecedented high order have been constructed to solve scalar-valued PDEs. We build on the aforementioned work in order to develop an Updated Lagrangian method for the solution of incompressible free surface flow subject to the inviscid Euler equations. The method is easy to implement and does not require any specific algorithmic treatment which is usually necessary to accurately resolve the incompressibility constraint. Due to its meshfree character, we will name it the Neural Particle Method (NPM). It will be demonstrated that the NPM remains stable and accurate even if the location of discretization points is highly irregular.