CEEC at the 12th National Conference on Flow Phenomena
2024-04-16 16:15 - 17:00 (Europe/Paris)
We will be presenting interem results from our work at the 12th National Conference on Flow Phenomena in Thessaloniki, Greece. If you’re going to be around (and speak Greek) please come say hello!

Center of Excellence in Exascale CFD at ISC High-Performance 2024
2024-05-15 14:15 - 14:45 | Congress Center Hamburg, Congressplatz 1, Hamburg, 20355, Germany
In addition to the technical programming, we will be presenting our last year of work at the EuroHPC Joint Undertaking booth J30 on Wednesday afternoon. Come hear about our latest work and then head over to Niclas’ talk on Neko later in the afternoon.

Neko: A Modern, Portable, and Scalable Framework for Extreme-Scale Computational Fluid Dynamics
2024-05-15 16:00 - 16:20 | Congress Center Hamburg, Congressplatz 1, Hamburg, 20355, Germany
Recent trends and advancements in including more diverse and heterogeneous hardware in High-Performance Computing are challenging scientific software developers in their pursuit of good performance and efficient numerical methods. As a result, the well-known maxim “software outlives hardware” may no longer necessarily hold true, and researchers are today forced to re-factor their codes to leverage these powerful new heterogeneous systems. We present Neko – a portable framework for high-fidelity spectral element flow simulations. Unlike prior works, Neko adopts a modern object-oriented Fortran 2008 approach, allowing multi-tier abstractions of the solver stack and facilitating various hard- ware backends ranging from general-purpose processors, accelerators down to exotic vector processors and Field Programmable Gate Arrays (FPGAs) via Neko’s device abstraction layer. Focusing on Neko’s performance and exascale readiness, we outline the optimisation and algorithmic work necessary to ensure scalability and performance portability across a wide range of platforms. Finally, we present performance measurements on a wide range of accelerated computing platforms, including the EuroHPC pre-exascale system LUMI and Leonardo, where Neko achieves excellent parallel efficiency for an extreme-scale direct numerical simulation (DNS) of turbulent thermal convection using up to 80% of the entire LUMI supercomputer.

Workshop on Readiness of HPC Extreme-scale Applications
2024-05-16 14:00 - 18:00 | Congress Center Hamburg, Congressplatz 1, Hamburg, 20355, Germany
If you have a workshop pass, please come hear about application development in the European HPC Centres of Excellence including CEEC!
“this ISC workshop has been organised to provide a forum to consider common challenges, ideas, solutions, and opportunities from the point of view of HPC applications developers preparing for exa-scale. ISC is the leading HPC conference in Europe, gathering not only the main HPC vendors and providers but also developers and standardizing committees from programming models, compilers, and other system software. However, we still need one of the key players in this ecosystem, the HPC applications! With this workshop, we seek to cover this gap and expand the ISC conference to HPC code developers.”

Neko: A modern, Portable, and Scalable Framework for High-Fidelity Computational Fluid Dynamics
2024-06-04 10:30 - 12:30 | Lisbon Congress Centre, Praça das Indústrias 1, Lisboa, 1300-307, Portugal
If you’ll be at ECCOMAS 2024, check out ‘Neko: A modern, Portable, and Scalable Framework for High-Fidelity Computational Fluid Dynamics’ presented by Niclas Jansson on the terrace.

ECCOMAS MS088 - State-of-the-art Machine Learning Techniques For Computational Fluid Dynamics
2024-06-04 14:30 - 16:30 | Lisbon Congress Centre, Praça das Indústrias 1, Lisboa, 1300-307, Portugal
Come join our Anna Schwarz, Jens Keim, and Andrea Beck for the mini-simposium “State-of-the-art Machine Learning Techniques For Computational Fluid Dynamics” in room 2.01.
Machine learning (ML) in scientific applications including computational fluid dynamics (CFD) is a growing field of research. However, ML can be less stable and more prone to errors in CFD because of its complexity relative to e.g. game theory. Thus, recent research has concentrated on reinforcement learning (RL) or physics-informed methods applied to CFD. Common examples for RL in CFD are flow control, turbulence modeling and shock capturing. An additional and continuously growing field of research which alleviates the common problems of ML in CFD is physics-informed neural networks (PINNs). In general, recently, modified versions of classical PINNs have been proposed to push their limitations and make them more tailored to CFD. With these considerations in mind, the objective of this minisymposium is to discuss the applicability, predictive performance and limitations of state-of-the-art ML methods in CFD.

A Fluid-Solid Coupled Micromechanical Simulation of Piping Erosion During the Installation of a Suction Bucket for the Foundation of an Offshore Wind Turbine
2024-06-04 17:00 - 19:00 | Lisbon Congress Centre, Praça das Indústrias 1, Lisboa, 1300-307, Portugal
If you’re not in the mini-symposium with Anna, make sure to come see Samuel Kemmler’s talk ‘A Fluid-Solid Coupled Micromechanical Simulation of Piping Erosion During the Installation of a Suction Bucket for the Foundation of an Offshore Wind Turbine’. It is part of the mini-symposium 020 – Advancements in Offshore Wind Structures , which will be held in Room 2.02.

Entropy stable subcell shock capturing scheme for high-order discontinuous Galerkin methods on moving meshes
2024-06-04 17:00 - 19:00 | Lisbon Congress Centre, Praça das Indústrias 1, Lisboa, 1300-307, Portugal
If you’re not in the mini-symposium with Samual, make sure to see the talk ‘Entropy stable subcell shock capturing scheme for high-order discontinuous Galerkin methods on moving meshes’ presented by Anna Schwarz in room 1.14.

Task-decomposed Overlapped Pressure Preconditioner for Sustained Strong Scalability on Accelerated Pre-exascale Systems
2024-07-16 17:30 - 18:00
Join CEEC in Kobe, Japan at the 12th bi-annual ICCFD conference this July! Niclas Jansson will be presenting “Task-decomposed Overlapped Pressure Preconditioner for Sustained Strong Scalability on Accelerated Pre-exascale Systems” as part of the technical program.

Mini-Symposium 4: Modernizing CFD: Exploring CI/CD for Improved Software Development Life Cycle
2024-09-02 00:00 - 2024-09-03 23:59 | Universitätsclub Bonn e.V., Konviktstr.9, Bonn, 53113, Germany
Join CEEC at the 35th Parallel CFD International Conference 2024 this fall in Bonn, Germany.
In the Mini-Symposium 4: Modernizing CFD: Exploring CI/CD for Improved Software Development Life Cycle, CEEC will be joined by sister European Centers of Excellence EXCELLERAT P2, EOCOE3, and HIDALGO 2 supported by the coordination activity CASTIEL 2. This symposium will focus on the role of Continuous Integration/Continuous Deployment (CI/CD) in guaranteeing CFD simulation applications’ stability, reproducibility, portability, and performance.

A continuous benchmarking pipeline for performance engineering on different architectures for the waLBerla framework
2024-09-03 16:50 - 17:10 | Universitätsclub Bonn e.V., Konviktstr.9, Bonn, 53113, Germany
Come listen to our own Kajol Kulkarni presenting in mini-symposium 4 at parCFD on our work with benchmarking of waLBerla.

Keynote Lecture at parCFD
2024-09-03 18:15 - 19:00 | Universitätsclub Bonn e.V., Konviktstr.9, Bonn, 53113, Germany
Join our own Niclas Jansson for his keynote lecture as an invited speaker at the 35th Parallel CFD International Conference 2024 in Bonn, Germany.

'Enabling mixed-precision with the help of tools: A Nekbone case study' at PPAM24
2024-09-09 12:05 - 12:25 | Ostrava, Czechia, Ostrava, Czech Republic
If you’re going to PPAM24 September 8 – 11 in Ostrava, Czechia, make sure to check out the talk by Yanxiang Chen from our partner UMU on their progress implementing and optimizing mixed precision in Nekbone toward its integration in Neko and NekRS. The accompanying paper is also available as a pre-print online: https://arxiv.org/pdf/2405.11065

Introduction to Computational Fluid Dynamics
2024-09-16 - 2024-09-20 | HLRS University of Stuttgart, Nobelstraße 19, Stuttgart, 70569, Germany
Join our Anna Schwarz as one of the instructors for the reoccuring “Introduction to Computational Fluid Dynamics” course organized by HLRS, IAG (University of Stuttgart) and the
Institute of Software Methods for Product Virtualisation (DLR).

FLEXI/GALÆXI: Open-Source Solver for Multiscale Flows
2024-10-30 11:00 - 12:00
Join us for the 11th CASTIEL Code of the Month to learn about FLEXI/GALÆXI!
In the field of computational fluid dynamics (CFD), high-order methods have reached a certain level of maturity for the solution of unsteady multiscale problems, of which turbulence is a prime example. For these types of problems, high-order schemes have proven to be efficient alternatives to more traditional numerical schemes. Among the high-order discretization variants, the discontinuous Galerkin method offers a collection of features which increased its popularity. In order to take full advantage of the potential benefits of these methods, all steps in the simulation chain, from pre- to post-processing, must be designed and executed with high-order in mind.
In this talk, we will present the open-source CFD frameworks FLEXI/GALÆXI, which are continuously developed by the Numerics Research Group of Prof. Andrea Beck at the Institute of Aerodynamics and Gas Dynamics at the University of Stuttgart. Both solvers provide a high-order consistent simulation tool chain for solving the compressible Navier–Stokes equations in a highly efficient, accurate and robust manner in a high performance computing setting either on CPU-based systems (FLEXI) or GPUaccelerated clusters (GALÆXI). The talk commences with a description of the numerical algorithms and implementation details, accompanied by an outline of the features and capabilities of all parts of the framework. In addition to these technical details, we also discuss the significant issues of code stability, reproducibility and user-friendliness. The advantages gained by developing an open-source framework are addressed, with a particular focus on usability for the open-source community. We conclude with application examples that demonstrate the wide range of use cases and the extensibility of FLEXI, as well as an overview of current and future developments.
Registration:
https://forms.office.com/e/P4Kr9xweRN

Introduction to the DLB Library
2024-11-13 15:00 - 16:00 | Online
The Dynamic Load Balancing library is a runtime library that offers different capabilities to HPC users. It consists of three different modules that work collaboratively and independently:
• Lend When Idle (LeWI): Offers a transparent load balancing mechanism for hybrid applications (MPI + OpenMP)
• Tracking Application Life Performance (TALP): Collects performance metrics at runtime, offering a transparent and lightweight tool to measure the parallel and computational efficiency of your code. Metrics can be collected during runtime, offering the possibility of dynamic adaptation.
• Dynamic Resource Ownership Management: Provides a mechanism to change the amount of computational resources used by the different processes at runtime without stopping the application.
In this tutorial we will provide an overview of the DLB library and each one of its modules. For each module we will share its main features, how to use it, and some success stories.

Call for Abstracts! High-fidelity CFD with application in ship hydrodynamics
2024-12-15 00:00 - 23:59
Submit your abstract to our invited session at Marine 2025!!
The session titled “High-fidelity CFD with application in ship hydrodynamics” is seeking submissions by December 15th, 2024. Full details and guidelines for submission are available in the proposal .
You can also check out the invited session’s page on the conference website.

Programming complex workflows with PyCOMPSs
2024-12-16 11:00 - 12:00 | Online
Programming large-scale systems poses several challenges to scientific application developers. Systems are growing in complexity, and concurrency is not the only difficulty that programmers face. They also contend with the distribution of memory spaces, complex architectures, new storage technology, etc. Task-based programming models have proven to be a good alternative to traditional programming models for HPC. PyCOMPSs is a pioneering approach to task-based programming in Python that enables codes to be executed in distributed computing platforms. In particular, PyCOMPSs supports different types of tasks, such as parallel simulations (MPI), artificial intelligence, or data analytics. This webinar will give an overview of PyCOMPSs illustrated with examples in development at BSC that include CFD simulations with AI training or real-time visualization in the same workflow.

Scientific Visualization for Exascale Simulations
2025-01-20 12:30 - 12:50 | Room 9
Join our own Susanne Malheiros for her presentation “Scientific Visualization for Exascale Simulations” at HiPEAC25!
Part of the workshop “From petascale to exascale and beyond: the Centres of Excellence challenge”, Susanne will present her work on visualizing exascale CFD and multi-physics simulations like our Localized Erosion of Wind Turbine foundations lighthouse case.

Exploring quantum computing in CoEs
2025-01-22 10:00 - 10:20 | Room 9
Join our Pratibha Raghupati to learn about her experience exploring the potential of quantum in the context of work being done by the European HPC Centers of Excellence!
Part of the workshop “Tackling software exascale challenges: the Centres of Excellence in High Performance Computing perspective”, she will present the potential impact of quantum in the context of exascale CFD simulations we’re working on in CEEC.

GALEXI: Scale-resolving simulations of compressible turbulence on GPU-accelerated systems
2025-01-22 14:00 - 14:20 | Room 9
Joine our Anna Schwarz for her talk “GALEXI: Scale-resolving simulations of compressible turbulence on GPU-accelerated systems”, part of the workshop “Tackling Software Exascale Challenges: the Centres of Excellence in High-Performance Computing Perspective”. She will present GALEXI, the GPU version of FLEXI, and the grogress she’s made in CEEC preparing these codes for exascale CFD simulations.

Vistle Part I: An Introduction to Immersive Visualizations of Large-Scale Scientific Data
2025-01-29 10:00 - 11:00
Save the date for our next webinar!
This one-hour webinar introduces the visualization tool Vistle, which is used to create augmented reality/virtual reality visualizations of large-scale scientific datasets. It presents Vistle’s remote rendering functionality and how Vistle is being ported to GPUs as part of the CEEC project to enable visualization for exascale datasets.
Agenda

Introducing Vistle

Examples of Immersive Visualizations
The Visualization Pipeline

Preparing Vistle for the Exascale Era

Hybrid Remote Rendering
Adding GPU support with VTK-m

Neko: A Modern, Portable, and Scalable Framework for Extreme-Scale Computational Fluid Dynamics
2025-03-03 10:45 - 11:00
Join our own Niclas Jansson at the SIAM Conference on Computational Science and Engineering (CSE25) in Fort Worth, Texas, for his talk “Neko: A Modern, Portable, and Scalable Framework for Extreme-Scale Computational Fluid Dynamics” in the mini-symposium MS19: Performance Benchmarking of Scientific Libraries and Applications.
Recent trends and advancements in utilizing more diverse and heterogeneous hardware in High-Performance Computing (HPC) are challenging scientific software developers in their pursuit of efficient numerical methods with sustained performance across a diverse set of platforms. As a result, researchers are bing forced to refactor their codes to leverage these powerful new heterogeneous systems. We present our work on addressing the extreme-scale computing challenges in computational fluid dynamics, ensuring exascale readiness of turbulence simulations. Focusing on Neko, a high-fidelity spectral element code, we outline the optimisation and algorithmic work necessary to ensure scalability and performance portability across a wide range of platforms. Finally, we present performance measurements on a wide range of accelerated computing platforms, including the EuroHPC pre-exascale systems LUMI and Leonardo, where Neko achieves excellent parallel efficiency for an extreme-scale direct numerical simulation (DNS) of turbulent thermal convection using up to 80% of the entire LUMI supercomputer.

Enabling mixed-precision with VerifiCarlo: Sharing CEEC experience
2025-03-04 10:00 - 11:00
Join our own Roman Iakymchuk, Umeå University on behalf of CEEC, and Pablo de Oliveira Castro, Université Paris-Saclay UVSQ, for the next in our webinar series this time on mixed precision and VerifiCarlo!
Driven by the increasing need to reduce the energy consumption of computing centers and simulations, scientists have begun revising applications, algorithms, and their underlying working/storage precision not just for performance but also for energy efficiency. The goal is to make computational costs sustainable while adhering to the lagom principle—using precision that is “just right” to balance accuracy with efficiency.
However, before lowering precision, one must ensure that the simulation is numerically correct. Verificarlo is an open-source framework designed to verify and optimize numerical accuracy in complex programs. Built on the LLVM infrastructure, it provides various floating-point backends to simulate the effects of numerical errors and lower precision. By leveraging alternative floating-point models, such as Stochastic Rounding, Verificarlo pinpoints numerical bugs in simulation codes. A probabilistic definition of the number of significant digits allows us to estimate computational accuracy accurately.
Through its variable precision backend, Verificarlo enables one to explore the trade-offs between precision and performance by simulating lower precisions in software. It identifies specific code regions that benefit from reduced floating-point formats without sacrificing numerical correctness. This approach has been successfully applied in high-performance computing (HPC) domains such as neuroimaging pipelines, DFT quantum mechanical modeling, structural simulations, and now CFD.
In this webinar, we will introduce Verificarlo, showcase its backends for numerical bug detection and mixed-precision analysis, and present a success story highlighting the road from analysis of codes with Verificarlo to reliable mixed-precision codes.

3rd CEEC Community Workshop - Vistle Part II: Hands-On Workshop for 3D Data Visualization
2025-05-21 15:00 - 17:00 | HLRS University of Stuttgart, Nobelstraße 19, Stuttgart, 70569, Germany
Join us for Part II of our Vistle series on site in Stuttgart!
In this hands-on two-hour workshop, you will get to know Vistle, a powerful open-source visualization tool, and learn how to create compelling 3D representations of scientific datasets, both in desktop as well as Virtual Reality environments. After an introduction to the software and its key features, you will have the opportunity to apply your knowledge and create your own visualization.
The workshop will be held on-site in Stuttgart at HLRS, the High-Performance Computing Center Stuttgart. For information on reaching HLRS and where to stay, please see the HLRS contact us page.
Check-in is available starting at 14:00 CEST including a tour of the HLRS CAVE. The workshop then begins at 15:00 CEST.
For any other questions about the workshop, please contact us!

Mixed-Precision and Energy-Efficient Computations
2025-06-10 15:00 - 2025-06-12 16:00
As supercomputers get bigger, they become both more capable of solving complex problems and consuming enormous amounts of energy. To ensure their sustainability, we must start focusing on reducing energy-to-solution at least as much as we focus on reducing time-to-solution. One of the ways CEEC is working on this is using mixed precision.
Join Yanxiang Chen at ISC in the Foyer D-G – on the 2nd floor to learn about our latest work reducing precision and energy consumption without compromising accuracy.

CEEC at ISC25
2025-06-11 13:00 - 13:20
Join our own Niclas Jansson at the Euro HPC JU booth for a presentation on our project and progress so far!

RESEARCH POSTER PITCH with Yanxiang Chen
2025-06-11 13:30 - 14:15
After listening to Niclas Jansson present our project at the EuroHPC JU booth at 1pm, strole over to Hall E to hear from our own Yanxiang Chen.
If you want the chance to ask questions about how we’re using mixed precision to drive energy-to-solution down without compromising accuracy, make sure to stop by the research poster pitch !
Yanxiang will present and answer questions about his poster Mixed-Precision and Energy-Efficient Computations.

Fully-resolved LBM-DEM simulations of piping erosion during a suction bucket installation
2025-07-01 00:00 - 2025-07-05 00:00 | Arcrea HIMEJI, 143-2, Kamiyacho, Himeji-City, Hyogo, 670-0836, Japan
Join our Samuel kemmler in Himeji, Japan for the 10th International Conference on Discrete Element Methods (DEM10) this summer!
Suction bucket foundations are a cost-efficient and environmentally sustainable solution to install offshore wind turbines, achieved through the application of growing suction pressure inside the bucket until its full embedment into the seabed. A key challenge for the installation process is the occurrence of piping erosion, a phenomenon where fluidization of particles beneath the bucket wall tip causes a drop in suction pressure, potentially leading to installation failure. Despite its significance, the complex physical mechanisms driving piping erosion remain insufficiently understood. To address this knowledge gap, a three-dimensional, fully-resolved coupled LBM-DEM simulation is employed to conduct an in-depth analysis of piping erosion, aiming to identify key influencing parameters, thus enhancing understanding and optimizing the installation process. The simulation of physically relevant problem sizes – comprising hundreds of thousands of grains – is equivalent to computational intensities which demand for extensive computational resources. Results from simulations executed on hundreds of GPUs on the LUMI supercomputer are presented, illustrating the method’s capability to tackle this complex challenge.

FLEXI: Scale-resolving simulations of compressible turbulence on modern HPC systems
2025-08-27 16:20 - 16:40 | TUD Dresden University of Technology Barkhausen-Bau (BAR), Georg-Schumann-Str. 13 , Dresden, 01069, Germany
Join our own Anna Schwarz for the WHPC Europa invited session discussing our latest work preparing FLEXI for exascale and GPU-based systems.
Abstract
The application of scale-resolving simulations such as LES and DNS remains challenging in numerous engineering applications due to the substantial computational demands and the limited available computational resources. It was thoroughly demonstrated in the last decade that high-order numerical methods show significant advantages in terms of computational cost required to achieve a given accuracy for DNS and LES and that they can be implemented efficiently on traditional CPU-based system architectures. However, the improvements in performance for CPU-based systems has slowed down significantly over the last years. Consequently, more specialised architectures, such as GPUs, have become increasingly popular in the last decade. These architectures still promise considerable performance improvements per generation and thus allow more complex flow cases to be tackled, while also yielding better performance per invested amount of energy. However, CPU codes cannot be easily run on GPU hardware, since they exhibit a distinctly different architecture and require different programming languages. In this talk it is demonstrated how existing codebases can be translated efficiently to GPU hardware, both in terms of implementation effort and computational performance. For this, the unstructured DG code FLEXI~cite{Krais2019,Kempf2024} is utilized as an example. Finally, it is shown that FLEXI is capable of tackling challenging large-scale problems with complex geometries on modern HPC systems.
