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The 27 March 2023

High order discontinuous spectral methods for massively parallel LES

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Cerfacs is Qualiopi certified for its training activities

Duration : 1 day (7 hours)            Cancelled

Satisfaction index

In November 2021, 100% of the participants were satisfied or very satisfied

(results collected from 6 respondents out of 8 participants, a response rate of 75%)


Large Eddy Simulation (LES) needs accurate schemes with enhanced spectral properties (low dissipation and low dispersion). Even if standard high order schemes (WENO, compact…) respect this need for structured grids, the situation is less clear for complex geometries, where unstructured grids are required.
The discontinuous spectral methods were introduced in order to circumvent the drawbacks of standard methods on unstructured grids. In this case, any conservative quantity is defined as a local polynomial in a control volume through its definition in several degrees of freedom per cell.
During this training, we will introduce these approaches defines as spectral discontinuous. After a bibliographic review, attention is paid on applications performed with the in-house solver JAGUAR developed at CERFACS and based on a discontinuous spectral formalism.

Objective of the training

To learn about spectral discontinuous approaches and to know how to realize LES computations with them.

Learning outcomes

The participants should be able to :

  • explain the differences between the different numerical schemes,
  • chose the good number of iterations in order to reach the convergence,
  • use the good sub-grid model,
  • chose the good size of unstructured grids,
  • being able to simulate academicals configurations.

Teaching methods

The training is an alternation of theoretical presentations and practical work. A multiple choice question allows the final evaluation. The training room is equipped with computers, the work can be done in sub-groups of two people.

Referent teacher: Jean-François Boussuge

Target participants

This training session is for students, engineers, physicists and computer scientists who wish to reinforce or extend their theoretical background to the precise use and analysis of CFD simulations.


In order to follow this course, you need to:

  • Knowledge of Unix commands.
  • Knowledge of numerical flow simulations
  • The training can take place in French or English depending on the audience, level B2 of the CEFR is required.

To verify that the prerequisites are satisfied, the following questionnaires must be completed. You need to get at least 75% of correct answers in order to be authorized to follow this training session. If you don’t succeed it, your subscription will not be validated. You only have two chances to complete them.

Questionnaire 1 : https://forms.gle/VxkqRFfoqJSuoTBQ7

Questionnaire 2 : https://forms.gle/DL6QXxRDRNqKA5V1A


After completing the pre-requisite tests and obtaining at least 75% correct answers, you can register here

Deadline for registration: 15 days before the starting date of each training

Before signing up, you may wish to report us any particular constraints (schedules, health, unavailability…) at the following e-mail address : training@cerfacs.fr


  • Trainees/PhDs/PostDocs : 112 € excl. tax
  • CERFACS shareholders/CNRS/INRIA : 280 € excl. tax
  • Public : 560 € excl. tax


Day 1 morning:
Introduction and analysis of discontinuous spectral methods
– Discontinuous Galerkin
– Spectral Volume
– Spectral Difference
– Flux Reconstruction

Day 1 afternoon:

Effects of spectral discontinuous methods on a computational environment:
– High order mesh and curved elements,
– Splitting the mesh
– Post-treatment

Introduction to JAGUAR:
– Mesh and input file
– Boundary conditions
– Serial and parallel performance of JAGUAR

– Application of JAGUAR on several test cases. It is also possible to work on an attendee’s application.

Evaluation of learning

A final exam will be conducted during the training.



ISAF project : To accelerate the transition to SAFs, SAFRAN and CERFACS have together obtained an allocation of 44 million CPU hours on the LUMI-C super-computer as part of the EuroHPC Regular Access call in November 2022.

CERFACS |  11 March 2023

The objective of the ISAF project is to study the impact of SAFs (Sustainable Aviation Fuels) on engine operation and pollutant emissions, using high-fidelity Large Eddy Simulations (LES). The methodology developed at CERFACS combines Analytically Reduced Chemistry (ARC) with a multi-component evaporation model to capture the effect of fuel. The target configurations range from academic burners (CRSB at CORIA, SSB at DLR Stuttgart), to isolated industrial injection systems (MICADO at ONERA, HERON at CORIA) and complete annular combustor configurations (BEARCAT at SAFRAN, NTNU test bench).Read more

A CERFACS article distinguished in Scilight (https://doi.org/10.1063/10.0017474)

CERFACS |  9 March 2023

The recently published paper in Physics of Plasma: "3D particle-in-cell study of the electron drift instability in a Hall Thruster using unstructured grids," by W. Villafana, B. Cuenot, and O. Vermorel ( attracted the attention of Scilight (), whose goal is to present the most interesting research in the physical sciences published in AIP journals."Read more