Cerfacs Enter the world of high performance ...

Partial Differential Equations

Solving PDEs (partial differential equations) is one of the most important fundamental tasks for solving physics and engineering problems. Efficient numerical algorithms for existing and future computer architectures are one of the main targets. CERFACS performs research on the mathematical fundamentals and on application cases that are of specific interest for CERFACS shareholders, and for which the methods are developed and tested.

Research and progress in PDE methods is deeply rooted in functional analysis, but often the usefulness in practice will depend on the availability of an efficient implementation, and, in particular, the interface to numerical solvers from linear algebra, both direct and iterative. In some applications, unconventional methods, such as mesh-free and kinetic methods (such as the lattice Boltzmann method, LBM) and semistructured mesh methods combined with matrix-free techniques have shown superior potential for high performance computing. In terms of the resolution achieved and the efficiency of execution, we have demonstrated that such methods can outperform conventional techniques by several orders of magnitude. This gain in efficiency promises enormous savings  or, equivalently, a superior fidelity and improved predictive power of the simulations.

A – Legacy codes: CERFACS has successfully developed solvers for PDEs. This is the case of the LES reacting flow solver AVBP. Preparing such codes for future architectures is a continuing task at CERFACS. A related field of development for these legacy codes is fully adaptive meshing techniques to hide all meshing tasks for end users.

B – Future methods and solvers: Research in numerical PDEs is progressing rapidly. CERFACS explores promising paths for future PDE solvers. A special example is the LBM which is already studied intensively at CERFACS in coordination with leading laboratories in the field (M2P2 in Marseille, FAU Erlangen). The LBM can be implemented efficiently on certain architectures and is especially suited for manycore accelerators. In this field, the ALGO and CFD teams work together. In addition to the LBM approach, work has been carried out on another equally promising approach: SDM (Spectral Difference Method which is a family of high-oder discontinuous approach). The latter makes it possible to obtain very accurate LES simulations (up to now spatial order up to ten have been tested) with a competitive cost compared to traditional approaches. CERFACS developed its own platform called JAGUAR and since 2018 CERFACS shares the ownership and the development of this solver with ONERA.

NEWS

NextSim General Assembly and TC meeting

CERFACS |  16 September 2021

The General Assembly and TC Meeting took place on 15-16 September 2021. CERFACS is involved in the NextSim project (). The primary objective is to increase the capabilities of Computational Fluid Dynamics tools on extreme-scale parallel computing platforms for aeronautical design. This project has received funding from the European High-Performance Computing Joint Undertaking (JU) under grant agreement N° 956104. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Spain, France, Germany. This project has received funding from the Agence Nationale de la Recherche (ANR) under grant agreement N° ANR-20-EHPC-0002-02. For more information, please visit Read more


Sophie Valcke from Cerfacs co-authored a new book on atmosphere-ocean modelling

CERFACS |  18 August 2021

new book "Atmosphere-Ocean Modelling - Couling and Couplers” by Prof. Carlos R Mechoso, Prof. Soon-Il An and Dr Sophie Valcke has just been published by World Scientific. The present book fills a void in the current literature by presenting a basic and yet rigorous treatment of how the models of the atmosphere and the ocean are put together into a coupled system. Details are available at  Abstract: Coupled atmosphere-ocean models are at the core of numerical climate models. There is an extraordinarily broad class of coupled atmosphere-ocean models ranging from sets of equations that can be solved analytically to highly detailed representations of Nature requiring the most advanced computers for execution. The models are applied to subjects including the conceptual understanding of Earth’s climate, predictions that support human activities in a variable climate, and projections aimed to prepare society for climate change. The present book fills a void in the current literature by presenting a basic and yet rigorous treatment of how the models of the atmosphere and the ocean are put together into a coupled system. The text of the book is divided into chapters organized according to complexity of the components that are coupled. Two full chapters are dedicated to current efforts on the development of generalist couplers and coupling methodologies all over the worldRead more

ALL NEWS