/ml-cfd-lecture

Lecture material for machine learning applied to computational fluid mechanics

Primary LanguageJupyter NotebookGNU General Public License v3.0GPL-3.0

Machine learning in computational fluid dynamics

This repository contains resources accompanying the lecture machine learning in computational fluid dynamics provided by the Institute of Fluid Mechanics at TU Braunschweig. Note that slides, notebooks, and other resources will be regularly updated throughout the term.

Glossary

The following list of acronyms may help you when exploring notebooks and slides:

  • CFD - computational fluid dynamics
  • DL - deep learning
  • GPU - graphics processing unit
  • IEEE - Institute of Electrical and Electronics Engineers
  • IEEE 754 - IEEE standard for floating-point arithmetics
  • JIT - just in time (compiler)
  • LES - large eddy simulation
  • LHS - latin hypercube sampling
  • MAE - mean absolute error
  • ML - machine learning
  • MPI - message passing interface
  • MSE - mean squared error
  • PINN - physics-informed neural network
  • RANS - Reynolds-averaged Navier Stokes
  • TPU - tensor processing unit

Datasets

Both exercises and lectures sometimes require datasets. Usually, there are instructions how to create or extract the data yourself. For convenience, a downloadable snapshot of the latest data (20. Dec 2021) is provided, too.

Lectures

If equations in the lecture notebooks do not get rendered properly on Github, download the notebook and open it using jupyter-lab (refer to the first exercise session for an overview of dependencies and installation instructions).

# topic slides notebook
1 Course overview and motivation link view online
2 Finite-volume-based CFD in a nutshell link view online
3 Introduction to machine learning link view online
4 Predicting the stability regime of rising bubbles link view online
5 Computing highly accurate mass transfer at rising bubbles I link view online
6 Computing highly accurate mass transfer at rising bubbles II link view online
7 Analyzing coherent structures in flows displaying transonic buffets I link view online
8 Analyzing coherent structures in flows displaying transonic buffets II link view online
9 Reduced-order modeling of the flow past a cylinder link view online
10 Controlling the flow past a cylinder I link view online
11 Controlling the flow past a cylinder II link view online

Exercises

Prerequisites

The exercises are designed for native Linux operating systems like Ubuntu (recommended). They may also work on Windows Subsystem for Linux (WSL). To set up your system for the exercises, refer to the notebook accompanying exercise session 1.

Exercise sessions

# topic slides notebook
1 Setting up your system - view online
2 End-to-end simulations in OpenFOAM and Basilisk - view online
3 End-to-end machine learning project in PyTorch - view online
4 Building a robust path regime classification model in PyTorch - view online
5 Generation and processing of training data for regression - view online
6 Model creation in PyTorch and mass transfer simulations in OpenFOAM - view online
7 Principal component analysis of surface pressure data - view online
8 Dynamic mode decomposition of a buffeting flow - view online
9 Creating a reduced-order model in flowTorch - view online
10 Open-loop control of the flow past a cylinder in OpenFOAM - view online
11 Closed-loop control of the flow past a cylinder with OpenFOAM and PyTorch - view online

Getting and providing help and feedback

If you

  • get stuck solving an exercise problem
  • have technical issues
  • have theoretical questions about math or programming
  • think that some instructions or explanations might need improvement
  • want to report typos or logical errors
  • want to provide feedback and suggestions about the course

the easiest way to get in touch is to open a new issue in this repository. Before opening a new issue, please use the search function to see if a related issue was reported previously. It also helps greatly if you label your issue using one or more of the predefined labels (lecture, exercise, OpenFOAM, ...), and if you take some time to state your problem as clearly as possible. Note that everyone is welcome to participate in discussion and solving issues.

If you are a student at TU Braunschweig enrolled in the course Machine Learning in Computational Fluid Dynamics, you may also get in touch via the studIP platform or via mail. However, the issue-workflow described above is the preferred method.

References and other resources

Book recommendations

  • books for computational fluid dynamics
    • The OpenFOAM technology primer by T. Marić, J. Höpken, and K. G. Mooney
    • The finite volume method in computational fluid dynamics by F. Moukalled, L. Mangani, and M. Darwish
    • An introduction to computational fluid dynamics: the finite volume method by H. K. Versteeg and W. Malalasekera
  • books for linear algebra
    • Introduction to linear algebra by G. Strang
  • books for data-driven modelling and control
    • Data-driven science and engineering: machine learning, dynamical systems, and control by S. L. Brunton and J. N. Kutz
    • Dynamic mode decomposition: data-driven modeling of complex systems by J. N. Kutz, S. L. Brunton, B. W. Brunton, and J. L. Proctor
    • Grokking deep reinforcement learning by M. Morales
    • Deep learning with PyTorch by E. Stevens, L. Antiga, and T. Viehmann
  • books for programming
    • Python crash course by E. Matthes
    • C++ crash course: a fast-paced introduction by J. Lospinoso
    • The Linux command line by W. Shotts

Video content