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Centre de recherche fondamentale et appliquée spécialisé dans la modélisation et la simulation numériques, également centre de formation avancée, le Cerfacs, par ses moyens et son savoir-faire en calcul haute performance, traite des grands problèmes scientifiques et techniques de recherche publique et industrielle sur les secteurs suivants: AERONAUTIQUE&AUTOMOBILEESPACEENERGIEENVIRONNEMENT&CLIMAT
Ses effectifs sont de l'ordre de 100-150 chercheurs, ingénieurs et administratifs.

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LES ACTUALITÉS

Workshop sur ‘Extreme CFD’ à Toulouse du 17 au 21 juillet 2017

24 juillet 2017

L'ENSEEIHT a accueilli le premier workshop 'Extreme Computing' du 17 au 21 juillet dans le cadre du GIS SUCCESS ( cinq participants de CERFACS, CORIA, EM2C, IMAG, IMFT, LEGI and SAFRAN TECH ont travaillé ensemble sur neuf projets autour des codes YALES2 et AVBP pour développer des nouveaux...Lire la suite


Le Train du Climat primé par La Société Européenne de Météorologie

12 juillet 2017

 

“Le train du climat” a reçu le prix 2017 de la Société Européenne de Météorologie (EMS) pour la Médiation et la Communication. Il récompense le concept innovant de cette exposition itinérante qui a sillonné la France les mois précédant la...

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NOS PUBLICATIONS

Vermorel, O., Quillatre, P. and Poinsot, T. (2017) LES of explosions in venting chamber: a test case for premixed turbulent combustion models, Combustion and Flame, 183 (september), pp. 207-223

[pdf] [Supplementary Material]

@ARTICLE{AR-CFD-17-91, author = {Vermorel, O. and Quillatre, P. and Poinsot, T. }, title = {LES of explosions in venting chamber: a test case for premixed turbulent combustion models}, year = {2017}, number = {september}, volume = {183}, pages = {207-223}, journal = {Combustion and Flame}, abstract = {This paper presents a new experimental and Large Eddy Simulation (LES) database to study upscaling effects in vented gas explosions. The propagation of premixed flames in three setups of increasing size is investigated experimentally and numerically. The baseline model is the well-known laboratory-scale combustion chamber from Sydney (Kent et al. 2005, Masri et al. 2012); two exact replicas at scales 6 and 24.4 were set up by GexCon (Bergen, Norway). The volume ratio of the three setups varies from 1 to more than 10 000, a variation unseen in previous experiments, allowing the exploration of a large range of Reynolds and Damköhler numbers. LES of gaseous fully premixed flames have been performed on the three configurations, under different operating conditions, varying the number of obstacles in the chamber, their position and the type of fuel (hydrogen, propane and methane). Particular attention is paid to the influence of the turbulent combustion model on the results (overpressure, flame front speed) comparing two different algebraic sub-grid scale models, the closures of Colin et al. (2000) and Charlette et al. (2002), used in conjunction with a thickened flame approach. Mesh dependency is checked by performing a highly resolved LES on the small-scale case. For a given scale and with a fixed model constant, LES results agree with experimental results, for all geometric arrangement of the obstacles and all fuels. However, when switching from small-scale cases to medium-scale or large-scale cases this conclusion does not hold, illustrating one of the main deficiencies of these algebraic models, namely the need for an a priori fitting of the model parameters. Although this database was initially designed for safety studies, it is also a difficult test for turbulent combustion models. }, keywords = {Gas explosion; Large Eddy Simulation; Turbulent combustion model; Efficiency function}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/06/CFD_vermorel_CF_2017.pdf}, supplementaryMaterial = {http://cerfacs.fr/wp-content/uploads/2017/06/CFD_mmc1.mp4}}

Bridel-Bertomeu, T., Gicquel, L. Y. M. and Staffelbach, G. (2017) Large scale motions of multiple limit-cycle high reynolds number annular and toroidal rotor/stator cavitieslarge scale motions of multiple limit-cycle high reynolds number annular and toroidal rotor/stator cavities, Physics of Fluids, 29 (065115), doi:10.1063/1.4989861

[pdf] [doi]

@ARTICLE{AR-CFD-17-113, author = {Bridel-Bertomeu, T. and Gicquel, L.Y.M. and Staffelbach, G. }, title = {Large scale motions of multiple limit-cycle high reynolds number annular and toroidal rotor/stator cavitieslarge scale motions of multiple limit-cycle high reynolds number annular and toroidal rotor/stator cavities}, year = {2017}, number = {065115}, volume = {29}, doi = { 10.1063/1.4989861 }, journal = {Physics of Fluids}, abstract = {Rotating cavity flows are essential components of industrial applications but their dynamics are still not fully understood when it comes to the relation between the fluid organization and monitored pressure fluctuations. From computer hard-drives to turbo-pumps of space launchers, designed devices often produce flow oscillations that can either destroy the component prematurely or produce too much noise. In such a context, large scale dynamics of high Reynolds number rotor/stator cavities need better understanding especially at the flow limit-cycle or associated statistically stationary state. In particular, the influence of curvature as well as cavity aspect ratio on the large scale organization and flow stability at a fixed rotating disc Reynolds number is fundamental. To probe such flows, wall-resolved Large Eddy Simulation (LES) is applied to two different rotor/stator cylindrical cavities and one annular cavity. Validation of the predictions prove the method to be suited and to capture the disc boundary layer patterns reported in the literature. It is then showed that in complement to these disc boundary layer analyses, at the limit-cycle the rotating flows exhibit characteristic patterns at mid-height in the homogeneous core pointing the importance of large scale features. Indeed, Dynamic Modal Decomposition (DMD) reveals that the entire flow dynamics are driven by only a handful of atomic modes whose combination links the oscillatory patterns observed in the boundary layers as well as in the core of the cavity. These fluctuations form macro-structures, born in the unstable stator boundary layer and extending through the homogeneous inviscid core to the rotating disc boundary layer, causing its instability under some conditions. More importantly, the macro-structures significantly differ depending on the configuration pointing the need for deeper understanding of the influence of geometrical parameters as well as operating conditions.}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/07/CFD_BRIDEL_POF2017.pdf}}

Barthélémy, S., Ricci, S., Rochoux, M., Le Pape, E. and Thual, O. (2017) Ensemble-based data assimilation for operational flood forecasting – On the merits of state estimation for 1D hydrodynamic forecasting through the example of the “Adour Maritime” river, Journal of Hydrology, 552, pp. 210-224, ISSN 0022-1694, doi:10.1016/j.jhydrol.2017.06.017

[doi]

@ARTICLE{AR-CMGC-17-115, author = {Barthélémy, S. and Ricci, S. and Rochoux, M. and Le Pape, E. and Thual, O. }, title = {Ensemble-based data assimilation for operational flood forecasting – On the merits of state estimation for 1D hydrodynamic forecasting through the example of the “Adour Maritime” river}, year = {2017}, volume = {552}, pages = {210-224}, issn = {0022-1694}, doi = {10.1016/j.jhydrol.2017.06.017}, journal = {Journal of Hydrology}}

Arioli, M. and Benzi, M. (2017) A FINITE ELEMENT METHOD FOR QUANTUM GRAPHS, IMA Journal of Numerical Analysis, pp. 1-45, doi:10.1093/imanum/drx029

[pdf] [doi]

@ARTICLE{AR-PA-17-54, author = {Arioli, M. and Benzi, M. }, title = {A FINITE ELEMENT METHOD FOR QUANTUM GRAPHS}, year = {2017}, pages = {1-45}, doi = {10.1093/imanum/drx029}, journal = {IMA Journal of Numerical Analysis}, abstract = {We study the numerical solution of boundary and initial value problems for differential equations posed on graphs or networks. The graphs of interest are quantum graphs, i.e., metric graphs endowed with a differential operator acting on functions defined on the graph’s edges with suitable side conditions. We describe and analyze the use of linear finite elements to discretize the spatial derivatives for a class of linear elliptic model problems. The solution of the discrete equations is discussed in detail in the context of a (non-overlapping) domain decomposition approach. For model elliptic problems and a wide class of graphs, we show that a combination of Schur complement reduction and diagonally preconditioned conjugate gradients results in optimal complexity. For problems of parabolic type, we consider the use of exponential integrators based on Krylov subspace methods. Numerical results are given for both simple and complex graph topologies.}, keywords = {quantum graphs, finite element method, complex graphs, sparse matrices, iterative methods, diffusion on graphs, exponential integrators}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/03/Cerfacs-TR-17-54-1.pdf}}

Bessières, L., Leroux, S., Brankart, J. -M., Molines, J. M., Moine, M. -P., Bouttier, P. -A., Penduff, T., Terray, L., Barnier, B. and Serazin, G. (2017) Development of a probabilistic ocean modelling system based on NEMO 3.5: application at eddying resolution, Geoscientific Model Development, pp. 1091-1106, doi:10.5194/gmd-10-1091-2017

[pdf] [doi]

@ARTICLE{AR-CMGC-17-76, author = {Bessières, L. and Leroux, S. and Brankart, J.-M. and Molines, J.M. and Moine, M.-P. and Bouttier, P.-A. and Penduff, T. and Terray, L. and Barnier, B. and Serazin, G. }, title = {Development of a probabilistic ocean modelling system based on NEMO 3.5: application at eddying resolution}, year = {2017}, pages = {1091-1106}, doi = {10.5194/gmd-10-1091-2017}, journal = {Geoscientific Model Development}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/05/GLOBC-Article-Mai-Bessieres_et_al_GMD_2017.pdf}}

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LE CERFACS RECRUTE

Codes acoustiques pour prévoir les instabilités de combustion dans les turbines à gaz

 

Required Education / Niveau requis

Master ou Ecole d'ingénieur

Contexte

Les turbines à gaz peuvent exhiber de puissantes instabilités de...

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Méthodes d'ensemble pour la réanalyse de modèle de réservoir

 

Le Cerfacs recrute un chercheur ou une chercheuse ayant de l’expérience en assimilation de données, si possible...

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