As part of this year's Computational Fluid Dynamics and Simulation (CFDS) Lab Course, the LBRG organized an excursion to the HoreKa supercomputer at SCC, KIT.
The excursion marks the completion of an inspiring summer term with 38 registered participants from Engineering, Mathematics and Computer Science programs.

The CFDS Lab is offered by a funded collaboration between the Lattice Boltzmann Research Group (https://www.lbrg.kit.edu) and the Scientific Computing Center (https://www.scc.kit.edu/): Stephan Simonis, Mathias J. Krause, Gudrun Thaeter, Jasmin Hörter, and Martin Frank.
In the course, we enable students to efficiently use the large-scale computing infrastructures at KIT such as HoreKa for scientific simulations with highly efficient codes such as OpenLB.

This course is funded by the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments. More information on is available at https://www.lbrg.kit.edu/page/cfdslab.

We gratefully acknowledge the computing time for our course provided on the high-performance computer hashtag#HoreKa by the National High-Performance Computing Center at KIT (NHR-Verein, NHR-Alliance Karlsruhe Institute of Technology (KIT)). This center is jointly supported by the Federal Ministry of Education and Research and the Ministry of Science, Research and the Arts of Baden-Württemberg, as part of the National High-Performance Computing joint funding program.HoreKa is partly funded by the German Research Foundation.

Over the past four weeks, four members of LBRG visited the University of Liverpool as part of the European Project SeaDream.

- Mathias J. Krause gave several presentations to colleagues in Liverpool, Manchester, Cardiff, and Sheffield
- We planned the upcoming Spring School 2026 in Liverpool
- Work on our first project paper on fluid structure interaction made great progress.
A big thanks you to our partners at Liverpool, Mohaddeseh Mousavi Nezhad, Davide Dapelo and John Bridgeman, for their warm welcome and inspiring discussions – we’re looking forward to the next steps in SeaDream!

We’re proud to share that Dr. Pedro Henrique Narloch, a recent alumnus of UFRGS under the supervision of Prof. Dr. Marcio Dorn and a frequent visitor LBRG, has joined paretos as a Machine Learning Engineer.
Paretos is a provider of cutting-edge AI-technology for controlling complex processes, based in Heidelberg.

In August, Marcio Dorn and Mathias J. Krause Krause visited Pedro Henrique Narloch at paretos and discussed further opportunities for continuing joint interdisciplinary projects such as the successfully completed DAAD-funded ProBral initiative on Mesoscopic Molecular Dynamics Simulations.

We wish you all the best in your new role, Pedro Henrique Narloch!

In August, we had the pleasure of welcoming Prof. Dr. Marcio Dorn (SBCB Lab at UFRGS, Brazill, https://sbcb.inf.ufrgs.br/) at LBRG.

The longstanding Brazil-German collaboration between Mario Dorn and Mathias J. Krause Krause at LBRG has resulted in numerous staff exchanges at all academic career levels as well as workshops, publications and successful projects on Lattice Boltzmann Methods, Machine Learning, High-Performance Computing and cross-disciplinary fields of application.
This time, the project group planned future research collaborations and prepared the upcoming guest visits of expert scientists from SBCB Lab at LBRG in 2026.

We look forward to continuing the fruitful collaboration with Marcio Dorn and the SBCB Lab at UFRGS.

In September, Mathias had the pleasure to visit his alma mater Cardiff University / Prifysgol Caerdydd, where he was studying as an Erasmus scholar more than 20 years ago. He renewed and intensified his contacts to Emeritus Professor of Mathematics Tim Phillips and Reader in the School of Engineering Zhihua Xie. Besides research around Lattice Boltzmann Methods (LBM) and its applications, the organization of future collaborations were discussed as well as a revival of undergraduate student exchange programs.

Thank you, Cardiff — it was good to be back!

As part of this year's Computational Fluid Dynamics and Simulation (CFDS) Lab Course, the LBRG organized an excursion to the wind tunnel at the Laboratory of Building and Environmental Aerodynamics at IWU, KIT.
Dr. Christof Gromke and his team have guided the participants through the testing facilities and introduced fundamental concepts and research milestones of their lab.

The CFDS Lab is offered by a funded collaboration between the Lattice Boltzmann Research Group (https://www.lbrg.kit.edu) and the Scientific Computing Center (https://www.scc.kit.edu/): Stephan Simonis, Mathias J. Krause, Gudrun Thaeter, Jasmin Hörter and Martin Frank.

In the course, we enable students to efficiently use the large-scale computing infrastructures at KIT such as HoreKa for scientific simulations with highly efficient codes such as OpenLB.

This course is funded by the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments. More information on is available at https://www.lbrg.kit.edu/page/cfdslab.

In August, the LBRG had the pleasure of welcoming Prof. Dr. Ferdinand le Noble and Dr. Dietmar Gradl from the Zoological Institute at KIT for the final HighVis project meeting.
The multidisciplinary HighVis project is funded by a ZEISS Collaboration Catalyst grant initiated by ZEISS Group and Karlsruher Institut für Technologie (KIT) and aligns with the research goals of the KIT Center Health Technologies .

In this project we propose a novel approach to measure blood viscosity based on in vivo intravital microscopic imaging of dynamic blood flows in the microcirculation, and subsequent computational analysis of microcirculatory red blood cell behavior.
Blood viscosity is an independent risk factor for predicting cardiovascular diseases including heart infarct and stroke. Routine assessment of blood viscosity can prevent progression to organ failure and subsequent premature mortality.Currently, fast, non-invasive techniques allowing repetitive measurement of viscosity in relevant patient populations are lacking, whereas existing ex-vivo techniques are cumbersome and not suitable for regular diagnostics.Our new algorithms developed in HighVis efficiently solve an inverse problem based on non-Newtonian Navier-Stokes models and deliver blood dynamics characteristics including viscosity.

A big thank you to the project group, Shota Ito, Ferdinand le Noble, Dietmar Gradl, Mathias J. Krause, and Stephan Simonis and our collaboration partners Gerd Klose, Ali Fard, Christian Kungel, and Sophia Schmitt, for their contributions and insights throughout this exciting project!

Stay tuned for upcoming publications and follow-up initiatives building on this work.

On August 28th, LBRG visited ITT Rheinhutte Pumpen GmbH (www.rheinhuette.de) preparing the official start of a new VDMA project, in which LBRG and HS Offenburg will jointly develop LBM-based simulation tools for high-fidelity centrifugal pump calculations.

We were pleased to meet our project partners: Prof. Andreas Schneider from HS Offenburg, Dr.-Ing. Heiko Kipp from ITT Rheinhütte Pumpen GmbH, and Harald Frank from VDMA. As part of the meeting, we had the opportunity to tour ITT Rheinhütte Pumpen GmbH’s production facilities and discuss the initial steps of the project.

We look forward to this collaboration and to developing a state-of-the-art design instrument for next-generation pump technologies together with our partners.

Adrian Kummerländer, Fedor Bukreev, Dennis Teutscher, Marcio Dorn and Mathias J. Krause have published a new paper on the Optimization of single node load balancing for lattice Boltzmann method on heterogeneous high performance computers in the Journal of Parallel and Distributed Computing (JPDC).

While LBMs are particularly suited for highly parallel computational fluid dynamics simulations on heterogeneous HPC systems, the computationally dominant collide-and-stream loops commonly utilize only GPUs, leaving CPU resources underutilized. To overcome this limitation, this article proposes a novel load balancing strategy based on a genetic algorithm for bottom-up, cost-aware optimization of spatial domain decompositions. This approach generates subdomains and rank assignments inherently suited for cooperative execution on both CPUs and GPUs. Implemented in the open source framework OpenLB, the strategy is applied to turbulent flow reference cases, including a multi-physics reactive mixer. A detailed evaluation on heterogeneous HPC nodes demonstrates significant performance gains, achieving speedups of up to 87% compared to traditional GPU-only execution. This work therefore establishes cost-aware, bottom-up decomposition as a suitable strategy for exploiting the native heterogeneity of modern compute nodes.

We are delighted to welcome our new PhD student, Florian Kaiser, to the group. His research will focus on solving transport problems in process engineering using monolithic approaches, with a particular emphasis on the development and implementation of a monolithic FSI solver.

We are pleased to present a simulation of the deposition of magnetic particles using OpenLB, an open-source lattice Boltzmann method (LBM) software. High-gradient magnetic fishing (HGMF) is a downstream processing technique for biomolecules such as proteins. In the initial step, magnetic particles are coated with a layer containing specific ligands that bind to a designated target molecule. These particles are then introduced into a medium that contains the target molecule, allowing adsorption of the molecules onto the ligands. Subsequently, the particles are separated using a magnetized wire and transferred to another medium. Finally, an elution step is performed to recover the purified molecules. The simulation illustrates the deposition of magnetic particles on a magnetized single wire and models the magnetic separation step of the HGMF process. Dipole forces acting on the particles are taken into account through a coupled discrete element method–lattice Boltzmann method (DEM-LBM) approach, implemented within the open-source software OpenLB.

We present a rigorous analysis of the pseudo-potential lattice Boltzmann method (P-LBM), showing its convergence to a PDE under diffusive scaling. By linking model parameters directly to physical properties, we enable simulations with inputs in SI units—no empirical tuning required. The method is implemented in OpenLB and validated with R134a benchmark tests.

Further information can be found here

Research Assistant (f/m/d)

Institute: Institute of Applied and Numerical Mathematics (IANM), Karlsruhe Institute of Technology (KIT)

Team: Lattice Boltzmann Research Group (LBRG) – www.lbrg.kit.edu

This position is part of an exciting research project focused on advanced numerical modelling and simulation with a focus on sensitivity analysis and optimization for fluid dynamics, solid mechanics, and fluid-structure interaction (FSI) using lattice Boltzmann methods (LBM).

After familiarisation, remuneration is paid according to TV-L, E 13. This role provides the opportunity to pursue a doctorate (PhD degree).

Your Responsibilities:

• Development and implementation of efficient and scalable LBM algorithms for complex multi-physics problems, specifically in OpenLB (www.openlb.net)
• Development and application of adjoint-based and data-driven optimization methods
• High-performance computing (HPC) on modern GPU-accelerated architectures
• Scientific collaboration with internal and external partners
• Participation in teaching and supervision of students
• Presentation of results at international conferences and publication in peer-reviewed journals

Your Profile:

• Master’s degree (or equivalent) in applied mathematics, scientific computing, or a related field
• Strong background in optimization, numerical methods and scientific computing
• Experience in fluid dynamics, solid mechanics, or LBM is highly advantageous
• Programming skills in C/C++ or similar
• Experience with parallel computing is a plus
• Curiosity, creativity, and a collaborative mindset
• Very good written and spoken English skills; basic German skills

We Offer:

• An inspiring research environment in a dynamic and interdisciplinary research group at one of Europe’s leading technical universities
• Structured doctoral support and career development
• A vibrant campus life in the heart of Karlsruhe

Application:

Please send your application including a cover letter, CV, transcripts, and contact details of at least one reference as a single PDF file to:

PD Dr. Mathias J. Krause
E-mail: mathias.krause@kit.edu

From July 21-25, 2025, Mingliang Zhong attended the ICMMES 2025 conference in Wuhan, China. He presented his work on “Non-Intrusive and Intrusive Uncertainty Quantification for Lattice Boltzmann Method,” showcasing recent developments in UQ methods integrated with OpenLB. He also contributed a poster introducing OpenLB and its role in advancing CFD research and education. A highlight of the event was a discussion with Zhaoli Guo, a leading expert in the LBM community.

We are pleased to announce our new paper, “A digital urban twin enabling interactive pollution predictions and enhanced planning,” was published in the journal Building and Environment. This work was made possible through the contributions of Dennis Teutscher, Fedor Bukreev, Adrian Kummerländer, Stephan Simonis, Peter Bächler, Ashkan Rezaee, Mariusz Hermansdorfer, and Mathias J. Krause.

This paper presents a novel approach for developing a digital twin of a city. By leveraging the computational power of GPUs in combination with the OpenLB simulation software, it becomes possible to dynamically update simulations using meteorological data such as wind speed, wind direction, and pollution levels. This enables real-time observation of pollutant dispersion and airflow patterns. The integration of automated geometry generation from OpenStreetMap data further allows the system to be adapted to various urban environments and scenarios.

This approach provides valuable support for advanced urban planning and decision-making by architects and policymakers.

You can read the full paper here: https://www.sciencedirect.com/science/article/pii/S0360132325005748

Stephan Simonis and Mathias J. Krause have published a new paper entitled "Limit consistency of lattice Boltzmann equations" in the ESAIM: M2AN journal.

The work establishes the notion of limit consistency as a modular part in proving the consistency of lattice Boltzmann equations with respect to a given partial differential equation system. Here, the incompressible Navier–Stokes equations are used as a paragon. Based on the hydrodynamic limit of the Bhatnagar–Gross–Krook (BGK) Boltzmann equation towards the Navier-Stokes equations, a successive discretization is proposed by nesting Taylor expansions and finite differences. As a direct result, the discretization technique of lattice Boltzmann methods is unfolded as chaining finite differences which provides a generic top-down derivation leading to the final numerical scheme.

The paper is available open access at https://www.esaim-m2an.org/articles/m2an/abs/2025/03/m2an240044/m2an240044.html

We are excited to present this student project by Maximilian Schecher (supervised by Adrian Kummerländer), which demonstrates free surface flow using the Lattice Boltzmann Method (LBM) within the open-source framework OpenLB.

Simulation Details:

• Model: D3Q27, single precision
• Resolution: 658,000 cells
• Fluid properties: density = 1000 kg/m³, kinematic viscosity = 1e-4 mm²/s
• Hardware: NVIDIA GeForce GTX 1080
• Setup & visualization by Maximilian Schecher
• Free surface implementation by Claudius Holeksa

The Video can be seen here: https://www.youtube.com/watch?v=PTT3mbFTjg8
For further information: https://openlb.net

We are pleased to announce that our new paper, “Predicting Filter Medium Performances in Chamber Filter Presses with Digital Twins Using Neural Network Technologies”, was published in the journal Applied Sciences. This work was made possible through the contributions of Dennis Teutscher, Tyll Weber-Carstanjen of the company SIMEX, Stephan Simonis and Mathias J. Krause.

In this paper, a novel approach to optimize the operation of chamber filter presses through digital twins powered by machine learning is presented. By leveraging sensor data and neural network models, we can accurately forecast key performance indicators such as pressure and flow rates, even in partially or completely unknown scenarios.

This advancement enables more efficient process monitoring, reduces downtime, and supports sustainable operation in solid-liquid separation processes. The full paper is available open-access here: https://www.mdpi.com/2076-3417/15/9/4933

We are honored to welcome Prof. Dr. Martin Geier from TU-Braunschweig. Martin is visiting us for a presentation on “Types of orthogonality in the Lattice Boltzmann Method with multiple relaxation rates”.EEWe sincerely thank Martin for his time and effort and look forward to future collaborations!

On April 30, 2025, Dr. Oliver Boolakee successfully defended his PhD thesis on "Lattice Boltzmann for Solids" at ETH Zürich. In his groundbreaking thesis, he proposed new second-order accurate lattice Boltzmann formulations for linear elasticity, considering both static and dynamic problem formulations. PD Dr. Mathias J. Krause, heading the LBRG at KIT, served as a co-examiner in the doctoral committee alongside Prof. Dr. Laura de Lorenzis (ETH Zürich), Prof. Dr. Barbara Wohlmuth (TU Munich), Prof. Dr. Martin Geier (TU Braunschweit) and Prof. Dr. Ralf Müller (TU Darmstadt).

We at LBRG (www.lbrg.kit.edu) are proud to look back on the following list of achievements in Education, Research and Innovation within the past years.

Education:

Finished theses at KIT: 12 dissertations, >100 bachelor/master/diploma theses

Teaching at KIT:

• Introduction to Computer Science and Algorithmic Mathematics:
  ~300 participants yearly (from Bio-/Chemical Engineering, and Mathematics)

• Parallel Computing in Theory and Practice: ~20 participants yearly (from Engineering and Mathematics)

• Computational Fluid Dynamics and Simulation Lab: ~35 participants yearly (from Engineering, Computer Science and Mathematics). Funded as part of the Excellence Strategy of the German Federal and State Governments.

• Seminar on Computational Fluid Dynamics: ~16 participants yearly (from Engineering and Mathematics)

International open workshops (such as "Lattice Boltzmann Methods with OpenLB Software Lab", https://www.openlb.net/spring-school):

• 105 participants / 18 countries: 8th Spring School, 2025, CIRM, Marseille, France.

• 10 participants / 3 countries: Industrial Workshop, 2024, Petronas, Kuala Lumpur, Malaysia.

• 57 participants / 13 countries: 7th Spring School, 2024, Heidelberger Akademie der Wissenschaften, Heidelberg, Germany.

• 50 participants / 15 countries: 6th Spring School, 2023, University of Greenwich, London, UK.

• 51 participants / 8 countries: 5th Spring School, 2022, AGH University of Science and Technology, Kraków, Poland.

• 60 particpants / 9 countries: 4th Spring School, 2020, TU Berlin, Berlin, Germany.

• 35 participants / 3 countries: DAAD PPP Workshop, 2019, UFRGS, Porto Alegre, Brazil.

• 46 participants / 12 countries: 3rd Spring School,2019, Technische Hochschule Mannheim, Mannheim, Germany.

• 10 participants / 3 countries: Workshop, 2019, Curtin University, Perth, Australia.

• 100 participants / >10 countries: Data-driven Modeling & Optimization Workshop, KIT, Karlsruhe, Germany.

• 49 participants / 14 countries: 2nd Spring School, 2018, KIT, Karlsruhe, Germany.

• 64 participants / 10 countries: 1st Spring School, 2017, Hammamet, Tunisia.

• 30 participants / 2 countries: HPC Workshop, 2017, IIT Mandi, India.

Research:

Editors for international journals:

• Computers & Fluids (@Mathias J. Krause, Associate Editor)

• Examples and Counterexamples (@Stephan Simonis, Associate Editor)

Publications:

110 Publications (excluding software), 17 software releases, and 2452 cites on Google Scholar

Third party funding:

7.37 million EUR from (DFG, EU, DAAD, InvestBW, BMBF, BMWi, industry and others)

Reviews:

• 40 publications international journals

• Reviews for international research funding agencies (DFG, SNF, ANR, ISF, EU Humboldt, KONWIHR, PACER, NHR)

Innovation:

Software: OpenLB (www.openlb.net), OpenGPI (www.opengpi.org), Paint2Sim, OpenVisFlow, OpenLBar, ClearMath (www.clearmaths.org)

Industrial collaborations with: Bosch, Henning Larsen, Kress, Mitsubishi Electric, Morgenrot, SEW Eurodrive, Yokogawa, Zeiss, Verband Deutscher Maschinen- und Anlagenbau, Naver Energy, Gavin and Doherty Geosolutions, Ashaw Energy, hr wallingford, Airbus, MSC Software | Hexagon, Euronovia

Our achievements are only possible with the joint work of our partners. For that we thank our collaborators at KIT as well as the national and international partners and are looking forward to future collaborative research.

International collaborations with LBRG (not exhaustive list):

• @Jürgen Rauleder (Georgia Institute of Technology)

• @Alexander Wagner (North Dakota State University)

• @Marcio Dorn (Federal University of Rio Grande do Sul)

• @Tianbai Xiao (Chinese Academy of Sciences)

• @Benjamin J. Mullins (Curtin University)

• @Timothy Reis (University of Greenwich)

• @Halim Kusumaatmaja (University of Edinburgh)

• @Timm Krüger (University of Edinburgh)

• @John Bridgeman (University of Bradford)

• @Mohaddeseh Mousavi Nezhad (University of Liverpool)

• @Siddhartha Mishra (ETH Zürich)

• @Laura de Lorenzis (ETH Zürich)

• @Ilya Karlin (ETH Zürich)

• @Julien Favier (Aix-Marseille Université)

• @Pierre Sagaut (Aix-Marseille Université)

• @Eduard Feireisl (Czech Academy of Sciences)

• @Miroslav Jicha (BRNO University of Technology)

• @Paweł Madejski (AGH University of Science and Technology)

• @Stephane Bordas (University of Luxembourg)

On the 8th of April, Mathias J. Krause and Fedor Bukreev from LBRG visited the Paul Scherrer Institute (PSI), where they presented recent LBM and OpenLB developments to Dr. Nikolaos Prasianakis and his group (Laboratory of Waste Management). The focus of the discussion was on microfluidics and flows in porous materials. LBRG looks forward to intensifying further cooperation with PSI.

From the 25th to the 27th of March, Mathias J. Krause and Christoph Gaul attended this year's DECHEMA specialist group meeting on particle technology at the Technical University of Clausthal. Christoph gave a presentation about the regeneration of wall-flow filters, which is part of a DFG project and was primarily worked on by Nicolas Hafen (doi:10.1017/jfm.2023.35).

Clausthal was a very pleasant location for the conference. While remote, it is a beautiful city with a fascinating history, having been an important center for mining for several centuries. The technical university remains deeply rooted in this field of expertise.

We attended several presentations on particle modelling and CFD. There were many interesting talks and posters from other groups working on particle simulations. We also visited SympaTec, a local company specializing in particle measurement, and discussed potential collaboration on an upcoming project.

We are excited to announce the publication of our article "Homogenized lattice Boltzmann methods for fluid flow through porous media – Part I: Kinetic model derivation" in the esteemed open-access journal ESAIM: Mathematical Modelling and Numerical Analysis (M2AN).

In our paper, we establish homogenized lattice Boltzmann methods (HLBM) for simulating fluid flow through porous media. Our contributions in this first part are twofold. First, we assemble the targeted partial differential equation system by formally unifying the governing equations for nonstationary fluid flow in porous media. Second, we propose a kinetic model, the homogenized Bhatnagar–Gross–Krook Boltzmann equation, which approximates the homogenized nonstationary Navier–Stokes equations (NSE). We formally prove that the zeroth and first order moments of the kinetic model provide solutions to the mass and momentum balance variables of the macroscopic model up to specific orders in the scaling parameter.

The article is published open-access in the ESAIM M2AN journal here

Based on the present paper, in the sequel (Part II appearing soon), the homogenized NSE will be consistently approximated by deriving a limit-consistent HLBM discretization of the homogenized Bhatnagar–Gross–Krook Boltzmann equation, and numerical limits will be explored based on efficient implementations in OpenLB

As a result of a five-month collaboration, we provide an example of a simulation on underground fluid storage using OpenLB, an open-source lattice Boltzmann method (LBM) software. One of the main challenges in subsurface fluid dynamics is dealing with complex rock structures and high-density ratio differences. In our study, we simulate gas (red) (hydrogen, methane, and CO2) displacing water (blue) in a real rock micro-fluidic device to analyze how underground formations can be optimized for fluid storage.

Key parameters of the presented simulation:

• Hydrogen injection into water-filled porous media
• Density ratio: 7.1 kg/m³ (H2) vs. 992 kg/m³ (H2O)
• Device size: 2 cm x 1 cm
• Pressure drop: 120 Pa
• Contact angle: 30°
• Resolution: 8.3448e-06 m

Our LBM D2Q19 phase-field multi-phase model is based on the Allen-Cahn approach, allowing for accurate tracking of phase interfaces and capillary effects.

This research, developed at Politecnico di Torino within the iENTRANCE project and partially implemented at the KIT Institute in collaboration with the OpenLB team, provides valuable insights into hydrogen storage and geological sequestration. Special thanks to Mathias J. Krause, Tim Bingert, and Luiz Eduardo Czelusniak for their contributions to the implementation and development of this work.

The presentation will be held on April 10th at 9:00 AM during the OMC Med Energy 2025 conference in Ravenna.

Raeli, A. et al. (2025). OMC Med Energy 2025 Ravenna. In Press, 8-10 Apr 2025.

The developer team is very happy to announce the release of the next version of OpenLB. The updated open-source Lattice Boltzmann (LB) code is now available for download

This release contains a plethora of new models, features and usability improvements. The addition of a wall model for fixed and moving walls usable together with a new platform-transparent fluid structure interaction module, physically parameterized multi-phase models and examples and a completely revamped code generation pipeline deserve special mention. Preliminary support for grid refinement operators should also not be forgotten.

The new release is also available in a public Git repository together with all previous releases.

We encourage everyone to submit contributions as merge requests and report issues there.

Core development continues within the existing private repository which is available to consortium members.

In March, Dr. Stephan Simonis presented a talk at the SIAM Conference on Computational Science and Engineering (CSE) in Fort Worth, Texas, US.

His talk on "Exploratory Computation of Statistical Solutions to Incompressible Fluid Flows" marks the starting point of a recently funded project in the DAAD PRIME program in collaboration with CAMLab at ETH Zürich . Within this project, the integration of efficient uncertainty quantification methods in OpenLB will enable the computation of time-dependent statistical solutions to boundary value problems described by Navier-Stokes and Euler models for turbulent fluid flow in three dimensions.

The abstract of the talk is available here .

We are pleased to present the simulation of dynamic Cross-Flow Filtration using OpenLB, an open-source lattice Boltzmann method (LBM) software.

One problem in filtration is the blocking of the filter by particles that deposit on the membrane (membrane fouling). This leads to a decrease in performance of the filter. To prevent the formation of a fouling layer, a flow tangential to the membrane is induced in cross-flow filtration. This can be achieved by a rotor. In a project at KIT this dynamic cross-flow device has been tested for the purification of proteins, since a high disperse phase fraction can be achieved.

Learn more at https://www.openlb.net/cross-flow-filtration/ or watch the YouTube video explaining the simulation at https://www.youtube.com/watch?v=Msh2iyG6-ho.

We are pleased to announce the successful defense of the dissertation by Mr. M. Sc. Jan Eric Marquardt, titled: "Modeling and Simulation of Suspension Dynamics Capturing Shapes and Contacts – With Applications"

Jan's outstanding scientific work was awarded the highest distinction, summa cum laude, in recognition of his exceptionally rigorous methodology, demonstrated interdisciplinary creativity, and, in particular, the sustainable and transparent implementation of his approch in the open-source software OpenLB (www.openlb.net).

His research has resulted in six first-author and five co-author publications. Notably, one of his recent papers was published in the prestigious journal Computer Physics Communications (Impact Factor: 7.2, Impact Factor7,2 --Marquardt, J. E., Hafen, N., and Krause, M. J. “A novel model for direct numerical simulation of suspension dynamics with arbitrarily shaped convex particles.” In: Computer Physics Communications 304 (2024), p. 109321. DOI:10.1016/j.cpc.2024.109321).

We warmly congratulate Dr.-Ing. Jan E. Marquardt on this remarkable achievement!

For further Information, you can take a look at the video at: https://www.youtube.com/watch?v=aC67MWXw468

We are excited to announce a new paper, written by Jan E. Marquardt, Bastian Eysel, Martin Sadric Cornelia Rauh and Mathias J. Krause on the damage to fruits during transportation.
Fruit preparations are used in various forms in the food industry. For example, they are used as an ingredient in dairy products such as yogurt with added fruit. The dispersed fruit pieces can be described as soft particles with viscoelastic material behavior. The continuous phase is represented by fluids with complex flow behavior depending on the formulation. Characterization has shown that the fluids exhibit a yield stress and pseudoplastic behavior, which can be described by the Herschel–Bulkley model. The analysis is performed numerically using the homogenized lattice Boltzmann method and validated by an experiment on industrial fruit preparations at pilot plant scale. The results show a strong dependence of the damage potential on the (local) Metzner–Reed Reynolds number.
For further information take a look at:
https://www.sciencedirect.com/science/article/pii/S0260877425000081?via%3Dihub

In the summer semester 2025, we will offer the Computational Fluid Dynamics and Simulation Lab. This interdisciplinary practical course focuses on applications of mathematics for simulations on high-performance computers, e.g., for computational fluid dynamics. Within this context, the interlocking concepts of mathematical modeling, numerical simulation (with lattice Boltzmann methods), high-performance computing, and presentation and evaluation of results are taught with the help of examples.

This course is funded by the Federal Ministry of Education and Research (BMBF) and the Baden-Württemberg Ministry of Science as part of the Excellence Strategy of the German Federal and State Governments.

More information is given on the course website or at https://www.lbrg.kit.edu/page/projsoftpr/ .

Also, in the summer semester 2025, we will offer the course Einstieg in die Informatik und Algorithmische Mathematik. This lecture aims to explain the basic concepts of algorithms and programming, with a special focus on C++.

We are excited to present a simulation on Protein Separation using OpenLB, an open-source lattice Boltzmann method (LBM) software.

One of the main problems in biotechnological production of active pharmaceutical ingredients is the separation of protein. Protein is dissolved in water and therefore difficult to remove. In an innovative method, developed by researchers of KIT, the protein absorbs at functionalized carrier particles.

Learn more at https://www.openlb.net/protein-separation/ or watch the YouTube video of the simulation at https://www.youtube.com/watch?v=i6mHgKJM1FQ .

We are happy to announce that we will extend our cooperation with Frantisek Prinz, Frantisek Lizal and many more from the Brno University of Technology. In March we first published a paper on paper on Comprehensive experimental and numerical validation of Lattice Boltzmann fluid flow and particle simulations in a child respiratory tract. Now we aim to study particle transport and deposition within the human respiratory system. This is essential for understanding various physiological and pathological processes as well as for developing effective drug delivery strategies. While considerable research has focused on male airway models, there is a growing recognition of the need to investigate female-specific airway geometries due to significant anatomical and physiological differences between sexes.

For the 1st paper take a look at: https://www.sciencedirect.com/science/article/pii/S0010482524000787

We are honored to welcome Yongbo Deng from Institute of Microstructure Technology (IMT)

Yongbo Deng is visiting us for a presentation on Topology Optimization of Micro and Nano Structures, which introduces a theoretical method for the development of Highly lightweight structures. This technique has numerous applications, metalenses in visible and infrared light, metalens arrays and many more.

We sincerely thank Yongbo Deng for his time and effort and look forward to future collaborations!

At the Institute of Mechanical Process Engineering and Mechanics (MVM) and the Institute of Applied and Numerical Mathematics (IANM) at the Karlsruhe Institute of Technology (KIT) we are looking for a Research assistant for our team Lattice Boltzmann Research Group (www.lbrg.kit.edu). Within the scope of a research project on the modelling and simulation of turbulent multi-component fluid flows, a full-time position is to be filled temporarily.

Besides enjoying scientific problem analysis as well as mathematical and/or process/chemical/mechanical engineering problems and/or computer science using parallel computers (CPU and GPU cluster), we expect you to have good programming skills, initiative, imagination and good communication skills in written and spoken German and English. Great importance is attached to working in a team.

Please send applications with the usual documents, preferably electronically in a pdf file, to mathias.krause@kit.edu

The SeaDream project strengthens EU efforts to achieve climate neutrality and to meet green energy and environmental targets.

SeaDream plays a crucial role in ensuring that marine energy is used sustainably and that coastal environments are preserved in line with EU policies.

The development of a high-resolution water-quality data service at sea is at the core of SeaDream’s mission. Data like these are crucial for addressing specific questions regarding maritime renewable energy generation and storage. In cooperation with the University of Luxembourg, the University of Liverpool, and several other partners, the Lattice Boltzmann Research Group (LBRT) at KIT will work on this project for four years.

Further information can be found at https://www.lbrg.kit.edu/page/seadream/. video of a Large Eddy Lattice Boltzmann Simulation of a Wind Park is available here: https://www.youtube.com/watch?v=dCAQiXfV50I

Registration is now open for the 8th Spring School 2025 on Lattice Boltzmann Methods with OpenLB and ProLB Software Lab that will be held in Marseille/France form 19.05.2025 – 23.05.2025.

The spring school introduces scientists and applicants from industry to the theory of LBM and trains them on practical problems. The first half of the week is dedicated to the theoretical fundamentals of LBM up to ongoing research on selected topics. Followed by mentored training on case studies using OpenLB or ProLB in the second half, where the participants gain deep insights into LBM and its applications. This educational concept is probably unique in the LBM community and offers a comprehensive and personal guided approach to LBM. Participants also benefit from the knowledge exchange during poster session, coffee breaks and the excursion. We look forward to your participation.

For more details and registration, visit https://www.openlb.net/spring-school-2025/.

We are pleased to announce that Christoph Gaul has joined our team as a new research staff member. His main topic of research will be Modelling ans Simulation of Particulate Flows. More percisely development of models and numerical methods for the simulation of particulate, turbulent and reactive flows for process engineering applications. For further information, visit https://www.lbrg.kit.edu/~christophgaul/ .

We are honored to welcome Philipp Spelten from the University of Siegen at the Lattice Boltzmann Research Group (LBRG) at KIT.

During his visit, Philipp worked on aeroacoustics and noise prediction for airfoils with Lattice Boltzmann Simulations in OpenLB.We would like to thank Philipp for his time and effort. We are looking forward to future collaborations.

We are excited to announce the publication on “Benchmark Simulation of Laminar Reactive Micromixing Using Lattice Boltzmann Methods” in the American Institute of Aeronautics and Astronautics Journal. There, we reestablish a benchmark for a reactive laminar micromixer using lattice Boltzmann methods (LBM) with special treatment of specie transport in secondary vortices resolved till the smallest Batchelor scale. This research was done with help of the open source CFD software OpenLB.

The article is published in the AIAA Journal under subscription: https://doi.org/10.2514/1.J064234 and is freely available as preprint at https://dx.doi.org/10.13140/RG.2.2.10086.64326

We are excited to announce the publication on “Calculation of Single and Multiple Low Reynolds Number Free Jets with a Lattice-Boltzmann Method” in the American Institute of Aeronautics and Astronautics Journal. In this research, we investigated behavior of a free jet and free jets bundle at distinct Reynolds numbers using lattice Boltzmann method and OpenLB. The article is published in the AIAA Journal under subscription: https://doi.org/10.2514/1.J064280

From October 6-11, 2024, the LBRG successfully organized the first OpenLB Hackathon in Feldberg, Germany. For one week, 14 group members focused on core development to further improve OpenLB in terms of boundary condition modeling, GPU support and user friendliness.

For the first time, we combined the lattice Boltzmann method (LBM) with the stochastic Galerkin (SG) method. The article is published open access in the Journal of Computational Physics and is freely available at https://doi.org/10.1016/j.jcp.2024.113344 . SG LBM extends LBM into the field of uncertainty quantification. As a proof of concept, we implemented parts of the approach in OpenLB and validated it using classical fluid dynamics benchmark tests with multidimensional uncertainty. In our numerical experiments, we achieved a speedup factor of 5.72 compared to Monte Carlo sampling, which demonstrates the high efficiency of SG LBM.

The lectures in the block seminar on computational fluid dynamics took place this week. Topics included particle distribution in the air after coughing, boiling water in microchannels, wind simulations around individual buildings and in residential neighbourhoods with different tree cover (in Dubai). We studied models with compressibility, with springs and for non-spherical particles. On Monday, 22 July at 1 pm, we will present the topics for next semester's seminar in room 3.069.

We have just released a new video on our OpenLB YouTube Channel. This is a first experimental showcase of OpenLB’s upcoming general purpose fluid structure interaction (FSI) capabilities. Visualized are various viewpoints on the vorticity norm of a two-way coupled four-turbine wind park setup with Reynolds number 1.2 Million. The simulation consisting of 1.5 billion cells utilized a single accelerated compute node of 4x NVIDIA H100 GPGPUs.
Computed on HoreKa Teal at KIT, the world’s sixth most energy efficient supercomputer.
Simulation & Visualization by Adrian Kummerländer
Visualization was generated in ParaView.

Last Friday (05.07.2024), the members of the Lattice Boltzmann Research Group (LBRG) received Prof. Dr. Alexander Wagner. His visit was marked by excellent research exchanges on Lattice Gas and Boltzmann Methods.

On June 14, 2024, the LBRG had the honor to host Prof. Dr. Eduard Feireisl (Czech Academy of Sciences, https://www.math.cas.cz/index.php/members/researcher/37) for a short research visit.

He gave a talk on dynamic homogenization of incompressible fluid flows (see https://arxiv.org/html/2404.06782v1) and worked together with Dr. Stephan Simonis, Adrian Kummerländer, Julius Jeßberger and PD Dr. Mathias J. Krause towards the numerical analysis of homogenized lattice Boltzmann methods (see https://arxiv.org/abs/2310.14746) for fluid structure interaction problems.

Last week LBRG attended the ECCOMAS Congress in Lisbon from 3rd to 7th June! Several members of LBRG presented their work.

▶ The techniques developed by the LBRG team are currently used for large eddy simulations of fluid-structure interaction with parallel solution of multiple coupled partial differential equations, and will soon contribute to providing aerodynamics-optimized geometries and reduced noise for wing elements within FALCON ✈

For more information auf FALCON please visit: https://www.lbrg.kit.edu/page/falcon/

The executive committee is happy to announce the closing of the 7^th LBM Spring School with OpenLB Software Lab. We hosted 57 participants from 13 countries this year. Congratulations to Jakob Scheel from the US for winning our poster award. We are already busy with organizing the next spring schools. The 8^th spring school is planned to take place in Marseille, France from May 19-23, 2025. We would like to thank all participants for attending the 7^th spring school in Heidelberg and acknowledge the support from our funders.

On behalf of the spring school executive committee (Kerstin Dick, Shota Ito, Mathias J. Krause and Stephan Simonis)

Paint2sim is a mobile application using a Lattice Boltzmann Method realized by the open-source simulation framework OpenLB. This innovative app allows users to scan hand-drawn domains and visualize 2D fluid flow simulations just-in-time on their mobile devices. Whether you're a student, researcher, or engineer, explore fluid dynamics with an intuitive interface with your fingertips. The app is freely available for download.

• Download and more information

For in-depth technical insights, refer to our latest paper, "Just-in-Time Fluid Flow Simulation on Mobile Devices Using OpenVisFlow and OpenLB"

Dennis Teutscher and his team developed the app paint2sim as part of the "teaching4future" project, with funding from the Lattice Boltzmann Research Group at KIT and the Ministry of Science, Research, and Arts of Baden-Württemberg, Germany.

The EU-funded project FALCON (Foreseeing the next generation of Aircraft: hybrid approach using Lattice-boltzmann, experiments and modelling to optimize fluid/struCture interactiONs) has started in January 2024 for a duration of 4 years and is coordinated by the Université d'Aix-Marseille, France. The project has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101138305. The FALCON partners (from 6 countries: Belgium, Czech Republic, France, Germany, Spain, UK) each bring unique expertise in experimental and numerical approaches in fluid and solid mechanics:
Aix-Marseille University,
Protisvalor,
Centre national de la recherche scientifique,
Centrale Méditerranée,
Airbus,
Karlsruhe Institute of Technology (KIT),
CS GROUP,
MSC Software,
German Aerospace Center (DLR),
IT4Innovations National Supercomputing Center,
Euronovia.

FALCON's goal is to enhance the design capabilities of the European industrial aircraft sector by focusing on fluid–structure interaction (FSI) phenomena to improve the aerodynamic performance of aircraft (unsteady loads). FALCON assembles a unique interdisciplinary environment of fifteen public and private institutions and their affiliated entities (from renowned research institutions to SMEs and aircraft high-tier suppliers and integrators) to cover all the required scientific and know-how expertise. Building upon three industrial test cases and tight links with key European partnerships such as Clean Aviation, FALCON delineates a high-impact/low-risk proposal that will significantly contribute to the digital transformation of the European aircraft supply chain.

The Lattice Boltzmann Research Group (LBRG) participated in the official kick-off meeting for FALCON (see LinkedIn).

Read more here

Nicolas Hafen successfully passed his doctoral thesis examination.

Congratulations to Nicolas and best wishes from the LBRG Team!

Heterogeneous Load Balancing in OpenLB: Cooperatively Utilizing CPUs and GPUs for a Turbulent Mixing Simulation

• YouTube Video
• More Information

We are proud to share that our paper "OpenLB—Open source lattice Boltzmann code" (https://doi.org/10.1016/j.camwa.2020.04.033) is ranked 5th on the list of "Top cited articles published in the past 3 years" in the journal Computers & Mathematics with Applications (IF 2.9, SJR Q1 in "Modeling and Simulation" and in "Computational Theory and Mathematics").

By the way, out of the first five articles in this list, two are on LBM-based software!

In addition, within the list of "The most downloaded articles in the last 90 days" our paper is ranking 6th. Three out of the first six papers in this list use #LBM.

Thank you to the community for citing us, to the team, the co-authors, the co-developers, and especially to Mathias J. Krause for leading the development of #OpenLB in the past years. 

You can download the latest release at https://www.openlb.net.

Sources
Scopus: 
https://www.scopus.com/

Elsevier:
https://www.sciencedirect.com/journal/computers-and-mathematics-with-applications

Stephan Simonis successfully passed his doctoral thesis examination entitled: "Lattice Boltzmann Methods for Partial Differential Equations".

Congratulations to the candidate and the reporters PD Dr. Mathias J. Krause, Prof. Dr. Siddhartha Mishra and Assoc. Prof. Dr. Tim Reis!

The executive committee is happy to announce the closing of the 6th LBM Spring School with OpenLB Software Lab. We hosted 50 participants from 15 countries this year. Congratulations to Martijn Gobes from the Netherlands for winning our poster award.

We are already busy planing next years spring school. The 7th spring school is planned to take place in Heidelberg/Karlsruhe in Germany from March 4th to 8th 2024. n.

Thank you all for attending the 6th spring school in Greenwich!

On behalf of the spring school executive committee.

On Tuesday, January 24th, 2023, the research collaboration between the Lattice Boltzmann Research Group (https://www.lbrg.kit.edu) at KIT and the CeMOS Research Center (https://www.cemos.hs-mannheim.de) at Hochschule Mannheim presented their results from the "Teaching4Future" research project funded by the Ministry of Science and Art. The aim was to make mathematical and process engineering concepts more understandable for students using XR technologies. Innovative apps such as OpenLBar (LBRG/KIT) and Paint2Sim (LBRG/KIT), as well as ARTIC (CeMOS), were introduced, enabling interaction, simulation, and visualization of 3D data through AR. The apps OpenLBar and soon Paint2Sim can be downloaded for free at https://www.openlb.net.

The numerous visitors had the opportunity to extensively test the apps and provide feedback during a relaxed get-together, which also included delicious Weißwürste and Brezeln.

Together with co-authors, members of the LBRG published their work on "Comprehensive Computational Model for Coupled Fluid Flow, Mass Transfer, and Light Supply in Tubular Photobioreactors Equipped with Glass Sponges" in Energies 2022, 15(20), 7671, doi: 10.3390/en15207671.

The article was selected as cover story for the current issue.

All simulations in the article have been conducted with OpenLB.

To celebrate the end of our time in home office due to Corona, the LBRG had a get-to-gether on June, the 6th. We enjoyed to meet again in person and got to know each other better while having a giant pretzel and a cup of coffee.

The pretzel is now honorary member known as OpenLBrezel.

The executive committee announces the closing of the fifth LBM Spring School with OpenLB Software Lab. We were happy to host 51 participants from 8 countries, including 4 invited speakers in Kraków, Poland. This year’s poster award goes to Pavel Eichler (Czech Technical University in Prague).

Next year, the 6th spring school is planned to take place at the University of Greenwich in England/UK from 2023 June 5th to 9th.

On behalf of the spring school executive committee, Nicolas Hafen, Mathias J. Krause, Paweł Madejski, Tomasz Kuś, Navaneethan Subramanian, Maciej Bujalski, Karolina Chmiel.

The LBRG presents its high performance fluid flow simulations using a desktop computer at the KIT campus day.

In March we had the opportunity to present some of our most recent projects at the annual FILTECH fair in Cologne. We discussed with visitors different topics around the lattice Boltzmann method as well as our open source software Open LB and its application. We further presented simulations results with our newly developed AR-App OpenLBar, which helps users to better understand and experience fluid flows through user interactions such as geometry overlay.

The head of LBRG Dr. Mathias J. Krause completed the habilitation examination on January 18, 2022. The thesis is titled Fluid Flow Control and Simulation in Process Engineering Homogenised Lattice Boltzmann Methods. He is now “Privatdozent (PD)” for the subject scientific computing and numerical mathematics for process engineering.