Lattice Boltzmann Fluid Simulations with the waLBerla Framework

Conference contribution
(Abstract of lecture)

Publication Details

Author(s): Bauer M, Rüde U
Publication year: 2016
Language: English


In the proposed talk we present a Python extension to the massively parallel HPC simulation toolkit waLBerla.
waLBerla is a framework for stencil based algorithms operating on
block-structured grids with the main application field being fluid
simulations in complex geometries using the lattice Boltzmann method.
Additionally, a free-surface extension based on a volume-of-fluid
approach and phase-field methods have been implemented in this
Careful performance engineering results in excellent node performance
and good scalability to over 400,000 cores. To increase the usability
and flexibility of the C++ framework, a Python interface was developed.

We embed the Python interpreter in existing waLBerla C++
application, providing the possibility to call Python functions from C++
code. These callbacks are used at all stages of the simulation
pipeline: They simplify and automate scenario setup, evaluation, and
plotting. We show how our Python interface outperforms the existing
text-file-based configuration mechanism, providing features like
automatic nondimensionalization of physical quantities and handling of
complex parameter dependencies. Furthermore, Python is used to process
and evaluate results while the simulation is running, leading to smaller
output files and the possibility to adjust parameters dependent on the
current simulation state.

waLBerla's central C++ data structures are exported such that a
seamless interfacing to other numerical Python libraries like numpy or
scipy is possible.
This is achieved by implemented the Buffer Protocol for waLBerla's
structured grids, such that they can be accessed in Python without
having to copy them.

Besides embedding the Python interpreter in C++ applications, we
additionally package the waLBerla framework as a Python module, such
that Python can be the driving language of the simulation. The module is
distributed using the conda package manager, and interactive Python notebooks are available as tutorial.

The flexibility and expressive power of Python enables the user to
develop code faster compared to C++. It is therefore also suitable for
prototyping of new methods or boundary conditions, a task that
previously was done using tools like Matlab. The Python interface of
waLBerla makes the framework more attractive for domain experts, which
typically are not familiar with C++ programming.

FAU Authors / FAU Editors

Bauer, Martin
Lehrstuhl für Informatik 10 (Systemsimulation)
Rüde, Ulrich Prof. Dr.
Lehrstuhl für Informatik 10 (Systemsimulation)

How to cite

Bauer, M., & Rüde, U. (2016). Lattice Boltzmann Fluid Simulations with the waLBerla Framework. Paper presentation at EuroSciPy, Erlangen, DE.

Bauer, Martin, and Ulrich Rüde. "Lattice Boltzmann Fluid Simulations with the waLBerla Framework." Presented at EuroSciPy, Erlangen 2016.


Last updated on 2019-24-04 at 05:21