论文标题
使用机器学习来增强粗网格计算流体动力学模拟
Using Machine Learning to Augment Coarse-Grid Computational Fluid Dynamics Simulations
论文作者
论文摘要
在高雷诺数字上对湍流的模拟是一项与气候科学,空气动力学和燃烧等各种领域中大量工程和科学应用相关的计算挑战性的任务。湍流通常由Navier-Stokes方程建模。具有足够数值分辨率的Navier-Stokes方程的直接数值模拟(DNS),可以捕获所有相关尺度的湍流运动尺度。在粗网格上以较低分辨率的模拟引入了重大误差。我们基于深度神经网络体系结构引入了机器学习(ML)技术,该技术纠正了在高雷诺数下的湍流模拟所引起的数值错误,同时恢复了高分辨率领域的估计值。我们提出的仿真策略是一种混合ML-PDE求解器,能够在较低分辨率求解系统PDE的同时获得有意义的高分辨率溶液轨迹。该方法有可能大大减少湍流模拟的费用。作为概念验证,我们在二维动荡(瑞利数字$ ra = 10^9 $)的ML-PDE策略中演示了Rayleigh-Bénard对流(RBC)问题。
Simulation of turbulent flows at high Reynolds number is a computationally challenging task relevant to a large number of engineering and scientific applications in diverse fields such as climate science, aerodynamics, and combustion. Turbulent flows are typically modeled by the Navier-Stokes equations. Direct Numerical Simulation (DNS) of the Navier-Stokes equations with sufficient numerical resolution to capture all the relevant scales of the turbulent motions can be prohibitively expensive. Simulation at lower-resolution on a coarse-grid introduces significant errors. We introduce a machine learning (ML) technique based on a deep neural network architecture that corrects the numerical errors induced by a coarse-grid simulation of turbulent flows at high-Reynolds numbers, while simultaneously recovering an estimate of the high-resolution fields. Our proposed simulation strategy is a hybrid ML-PDE solver that is capable of obtaining a meaningful high-resolution solution trajectory while solving the system PDE at a lower resolution. The approach has the potential to dramatically reduce the expense of turbulent flow simulations. As a proof-of-concept, we demonstrate our ML-PDE strategy on a two-dimensional turbulent (Rayleigh Number $Ra=10^9$) Rayleigh-Bénard Convection (RBC) problem.