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Cerfacs in brief

Centre of basic and applied research specialized in modelling and numerical simulation, Cerfacs, through its facilities and expertise in high-performance computing, deals with major scientific and technical research problems of public and industrial interest.

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NEWS

Cerfacs’ kraken configuration upgrade to more than 500 Tflop/s

superadmin |  2 October 2019

64 skylake nodes have been added to Cerfacs' cluster Kraken which offer now more than 7 000 skylake cores and 563 peak Tflop/s.Read more


67 climate modelling groups use OASIS3-MCT to assemble more than 80 coupled applications

superadmin |  10 September 2019

OASIS3-MCT is a coupler of codes developed at Cerfacs and used around the world, mainly for climate modelling applications. Our last survey confirms that OASIS3-MCT is used by 67 modelling groups to assemble more than 80 different coupled applications over the 5 continents. These applications include global or regional configurations of ocean and atmosphere models but also sea ice, sea level, wave, ocean biogeochemistry, land, vegetation, river routing, hydrological and atmospheric chemistry models. OASIS3-MCT is used in 5 of the 7 European Earth System Models participating to the 6th Coupled Model Intercomparison Project (CMIP6) that produces the climate simulations forming the basis of the next report of the Intergovernmental Panel on Climate Change (IPCC)”Read more

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RESEARCH PUBLICATIONS

Massoud, E. C., Xu, C., Fisher, R. A., Knox, R. G., Walker, A. P., Serbin, S. P., Christoffersen, B. O., Holm, J. A., Kueppers, L. M., Ricciuto, D. M., Wei, L., Johnson, D. J., Chambers, J. Q., Koven, C. D., McDowell, N. G. and Vrugt, J. A. (2019) Identification of key parameters controlling demographically structured vegetation dynamics in a land surface model: CLM4.5(FATES), Geoscientific Model Development, 12 (9), pp. 4133–4164, doi:10.5194/gmd-12-4133-2019

[pdf] [url] [doi]

@ARTICLE{AR-CMGC-19-135, author = {Massoud, E.C. and Xu, C. and Fisher, R.A. and Knox, R.G. and Walker, A.P. and Serbin, S.P. and Christoffersen, B.O. and Holm, J.A. and Kueppers, L.M. and Ricciuto, D.M. and Wei, L. and Johnson, D.J. and Chambers, J.Q. and Koven, C.D. and McDowell, N.G. and Vrugt, J.A. }, title = {Identification of key parameters controlling demographically structured vegetation dynamics in a land surface model: CLM4.5(FATES)}, year = {2019}, number = {9}, volume = {12}, pages = {4133–4164}, doi = {10.5194/gmd-12-4133-2019}, journal = {Geoscientific Model Development}, pdf = {https://cerfacs.fr/wp-content/uploads/2019/09/Globc-Article-Fisher-GeoSci.Mod_.pdf}, url = {https://www.geosci-model-dev.net/12/4133/2019/}}

Guillet, O., Weaver, A. T., Vasseur, X., Michel, Y., Gratton, S. and Gürol, S. (2019) Modelling spatially correlated observation errors in variational data assimilation using a diffusion operator on an unstructured mesh, Quarterly Journal of the Royal Meteorological Society, 145 (722), pp. 1947-1967, ISSN 0035-9009, doi:10.1002/qj.3537

[pdf] [doi]

@ARTICLE{AR-PA-19-127, author = {Guillet, O. and Weaver, A.T. and Vasseur, X. and Michel, Y. and Gratton, S. and Gürol, S. }, title = {Modelling spatially correlated observation errors in variational data assimilation using a diffusion operator on an unstructured mesh}, year = {2019}, number = {722}, volume = {145}, pages = {1947-1967}, issn = {0035-9009}, doi = {10.1002/qj.3537}, journal = {Quarterly Journal of the Royal Meteorological Society}, keywords = {correlation functions, diffusion operator, finite element method, observation errors, unstructured mesh, variational assimilation}, pdf = { https://doi.org/10.1002/qj.3537}}

Emili, E., Barret, B., Le Flochmoën, E. and Cariolle, D. (2019) Comparison between the assimilation of IASI Level 2 ozone retrievals and Level 1 radiances in a chemical transport model, Atmospheric Measurement Techniques, 12 (7), pp. 3963-3984, doi:doi.org/10.5194/amt-12-3963-2019

[pdf] [doi]

@ARTICLE{AR-CMGC-19-119, author = {Emili, E. and Barret, B. and Le Flochmoën, E. and Cariolle, D. }, title = {Comparison between the assimilation of IASI Level 2 ozone retrievals and Level 1 radiances in a chemical transport model}, year = {2019}, number = {7}, volume = {12}, pages = {3963-3984}, doi = {doi.org/10.5194/amt-12-3963-2019}, journal = {Atmospheric Measurement Techniques}, pdf = {https://cerfacs.fr/wp-content/uploads/2019/08/GLOBC-Article-EMILI-amt-12-3963-2019.pdf}}

Muscat, L., Puigt, G., Montagnac, M. and Brenner, P. (2019) A coupled implicit-explicit time integration method for compressible unsteady flows, Journal of Computational Physics, 398 (Article 108883), doi:10.1016/j.jcp.2019.108883

[url] [doi]

@ARTICLE{AR-CFD-19-120, author = {Muscat, L. and Puigt, G. and Montagnac, M. and Brenner, P. }, title = {A coupled implicit-explicit time integration method for compressible unsteady flows}, year = {2019}, number = {Article 108883}, volume = {398}, doi = {10.1016/j.jcp.2019.108883}, journal = {Journal of Computational Physics}, abstract = {This paper addresses how two time integration schemes, the Heun's scheme for explicit time integration and the second-order Crank-Nicolson scheme for implicit time integration, can be coupled spatially. This coupling is the prerequisite to perform a coupled Large Eddy Simulation / Reynolds Averaged Navier-Stokes computation in an industrial context, using the implicit time procedure for the boundary layer (RANS) and the explicit time integration procedure in the LES region. The coupling procedure is designed in order to switch from explicit to implicit time integrations as fast as possible, while maintaining stability. After introducing the different schemes, the paper presents the initial coupling procedure adapted from a published reference and shows that it can amplify some numerical waves. An alternative procedure, studied in a coupled time/space framework, is shown to be stable and with spectral properties in agreement with the requirements of industrial applications. The coupling technique is validated with standard test cases, ranging from one-dimensional to three-dimensional flows.}, keywords = {Hybrid time integration, Space-time stability analysis, Finite volume formulation, Compressible unsteady flows}, url = {https://doi.org/10.1016/j.jcp.2019.108883}}

Le Bras, S., Deniau, H. and Bogey, C. (2019) A technique of flux reconstruction at the interfaces of non-conforming grids for aeroacoustic simulations, International Journal for Numerical Methods in Fluids, doi:10.1002/fld

[doi]

@ARTICLE{AR-CFD-19-123, author = {Le Bras, S. and Deniau, H. and Bogey, C. }, title = {A technique of flux reconstruction at the interfaces of non-conforming grids for aeroacoustic simulations}, year = {2019}, doi = {10.1002/fld}, journal = {International Journal for Numerical Methods in Fluids}, abstract = {A flux reconstruction technique is presented in order to perform aeroacoustic computations using implicit high-order spatial schemes on multiblock structured grids with non-conforming interfaces. The use of such grids, with mesh spacing discontinuities across the block interfaces, eases local mesh refinements, simplifies the mesh generation process, and thus facilitates the computation of turbulent flows. In this work, the spatial discretization consists of sixth-order finite-volume implicit schemes with low-dispersion and lowdissipation properties. The flux reconstruction is based on the combination of non-centered schemes with local interpolations to define ghost cells and compute flux values at the grid interfaces. The flow variables in the ghost cells are calculated from the flow field in the grid cells using a meshless interpolation with radial basis functions. In this study, the flux reconstruction is applied to both plane and curved non-conforming interfaces. The performance of the method is first evaluated by performing two-dimensional simulations of the propagation of an acoustic pulse and of the convection of a vortex on Cartesian and wavy grids. No significant spurious noise is produced at the grid interfaces. The applicability of the flux reconstruction to a 3-D computation is then demonstrated by simulating a jet at a Mach number of 0.9 and a diameter-based Reynolds number of 4× 105 on a Cartesian grid. The non-conforming grid interface located downstream of the jet potential core does not appreciably affect the flow development and the jet sound field, while reducing the number of mesh points by a factor of approximately two. }}

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JOBS OFFERS

Permanent research position (CDI) in the field of High Performance Computation (HPC) and Coupling for Computational Fluid Dynamics of reacting flows

 

Context: CERFACS is the leader in the field of HPC simulations for combustion. It was the...Read more


Simulation of the emission of nitrogen oxides in a semi-industrial burner

 

Context Nitrogen oxides are one of the undesirable products of combustion, and many technical solutions are...Read more

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