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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

Invited communication to the BIDS'17 conference

thual |  12 December 2017

During an invited communication to the « Big Data from Space 2017 » conference, CERFACS presented the stakes and the perspectives of its strategic axis "Data Driven Modeling" from the point of view of the valorization of satellite data. For more details, see the article:...Read more


One Cerfacs’ proposal accepted in PRACE 15th call

superadmin |  4 December 2017

This study focuses on Hall-effect thrusters, which were first invented in the 1960s. Although such systems have been extensively studied, the detailed physics of the magnetized plasmas in these thrusters is very complex and several plasma processes that have direct influence on the thruster...Read more

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CALENDAR

RESEARCH PUBLICATIONS

Moreau, S., Becerril, C. and Gicquel, L. Y. M. (2017) Large-Eddy-Simulation prediction of indirect combustion noise in the Entropy Wave Generator experiment, International Journal of Spray and Combustion Dynamics, doi:10.1177/1756827717740775

[pdf] [doi]

@ARTICLE{AR-CFD-17-277, author = {Moreau, S. and Becerril, C. and Gicquel, L.Y.M. }, title = {Large-Eddy-Simulation prediction of indirect combustion noise in the Entropy Wave Generator experiment}, year = {2017}, doi = {10.1177/1756827717740775}, journal = {International Journal of Spray and Combustion Dynamics}, abstract = {Compact and non-compact analytical solutions of the subsonic operating point of the Entropy Wave Generator experiment are compared with detailed numerical results obtained by Large Eddy Simulations. Two energy deposition methods are presented to account for the experimental ignition sequence and geometry: a single-block deposition as previously used and a delayed deposition that reproduces the experimental protocle closely. The unknown inlet acoustic reflection coefficient is assumed to be fully reflective to be more physically consistent with the actual experimental setup. The time delay between the activation of the heating modules must be considered to retrieve the temperature signal measured at the vibrometer and pressure signals at the microphones. Moreover, pressure signals extracted from the LES in the outlet duct using the delayed ignition model clearly reproduce the experimental signals better than the analytical models. An additional simulation with actual temperature fluctuations directly injected at the inlet of the computational domain clearly shows that the pressure fluctuations produced by the acceleration of the hot slug yields indirect noise almost entirely. Finally the entropy spot is shown to be distorted when convecting through the turbulent flow in the EWG nozzle. Its amplitude decreases and its shape is dispersed, but hardly any dissipation occurs. The distortion appears to be negligible through the nozzle and become important only when convected over a long distance in the downstream duct. As the dominant frequencies of the EWG entropy forcing are very low, the effects of dispersion by the mean flow are however weak. }, keywords = {COMB, AVBP}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/12/CFD_BECERRILandal._SAGE2017.pdf}}

Bushuk, M., Msadek, R., Winton, M., Vecchi, G. A., Gudgel, R. G., Rosati, A. and Yang, X. (2017) Skillful regional prediction of Arctic sea ice on seasonal timescales, Geophysical Research Letters, 44, pp. 4953−4964, doi:10.1002/2017GL073155

[pdf] [doi]

@ARTICLE{AR-CMGC-17-278, author = {Bushuk, M. and Msadek, R. and Winton, M. and Vecchi, G.A. and Gudgel, R.G. and Rosati, A. and Yang, X. }, title = {Skillful regional prediction of Arctic sea ice on seasonal timescales}, year = {2017}, volume = {44}, pages = {4953−4964}, doi = {10.1002/2017GL073155}, journal = {Geophysical Research Letters}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/12/GLOBC-Article-Bushuk_GRL_DEC-2017.pdf}}

Paoli, R., Thouron, O., Cariolle, D., Garcia, M. and Escobar, J. (2017) Three-dimensional large-eddy simulations of the early phase of contrail-to-cirrus transition: effects of atmospheric turbulence and radiative transfer, Meteorologische Zeitschrift, 26 (6), pp. 597-620, doi:10.1127/metz/2017/0764

[url] [doi]

@ARTICLE{AR-AE-17-306, author = {Paoli, R. and Thouron, O. and Cariolle, D. and Garcia, M. and Escobar, J. }, title = {Three-dimensional large-eddy simulations of the early phase of contrail-to-cirrus transition: effects of atmospheric turbulence and radiative transfer}, year = {2017}, number = {6}, volume = {26}, pages = {597-620}, doi = {10.1127/metz/2017/0764}, journal = {Meteorologische Zeitschrift}, url = {http://dx.doi.org/10.1127/metz/2017/0764}}

Thiesset, F., Halter, F., Bariki, C., Lapeyre, C., Chauveau, C., Gökalp, I., Selle, L. and Poinsot, T. (2017) Isolating strain and curvature effects in premixed flame/vortex interactions, Journal of Fluid Mechanics, 831 (November), pp. 618-654, doi:10.1017/jfm.2017.641 618 Isolating

[doi]

@ARTICLE{AR-CFD-17-272, author = {Thiesset, F. and Halter, F. and Bariki, C. and Lapeyre, C. and Chauveau, C. and Gökalp, I. and Selle, L. and Poinsot, T. }, title = {Isolating strain and curvature effects in premixed flame/vortex interactions}, year = {2017}, number = {November}, volume = {831}, pages = {618-654}, doi = {10.1017/jfm.2017.641 618 Isolating}, journal = {Journal of Fluid Mechanics}, abstract = {This study focuses on the response of premixed flames to a transient hydrodynamic perturbation in an intermediate situation between laminar stretched flames and turbulent flames: an axisymmetric vortex interacting with a flame. The reasons motivating this choice are discussed in the framework of turbulent combustion models and flame response to the stretch rate. We experimentally quantify the dependence of the flame kinematic properties (displacement and consumption speeds) to geometrical scalars (stretch rate and curvature) in flames characterized by different effective Lewis numbers. Whilst the displacement speed can be readily measured using particle image velocimetry and tomographic diagnostics, providing a reliable estimate of the consumption speed from experiments remains particularly challenging. In the present work, a method based on a budget of fuel on a well chosen domain is proposed and validated both experimentally and numerically using two-dimensional direct numerical simulations of flame/vortex interactions. It is demonstrated that the Lewis number impact neither the geometrical nor the kinematic features of the flames, these quantities being much more influenced by the vortex intensity. While interacting with the vortex, the flame displacement (at an isotherm close to the leading edge) and consumption speeds are found to increase almost independently of the type of fuel. We show that the total stretch rate is not the only scalar quantity impacting the flame displacement and consumption speeds and that curvature has a significant influence. Experimental data are interpreted in the light of asymptotic theories revealing the existence of two distinct Markstein numbers, one characterizing the dependence of flame speed to curvature, the other to the total stretch rate. This theory appears to be well suited for representing the evolution of the displacement speed with respect to either the total stretch rate, curvature or strain rate. It also explains the limited dependence of the flame displacement speed to Lewis number and the strong correlation with curvature observed in the experiments. An explicit relationship between displacement and consumption speeds is also given, indicating that the fuel consumption rate is likely to be altered by both the total stretch rate and curvature}, keywords = {combustion, reacting flows}}

Monerie, P. A., Coquart, L., Maisonnave, E., Moine, M. -P., Terray, L. and Valcke, S. (2017) Decadal prediction skill using high-resolution climate model, Climate Dynamics, 49 (9-10), pp. 3527–3550, doi:10.1007/s00382-017-3528-x

[pdf] [doi]

@ARTICLE{AR-CMGC-17-274, author = {Monerie, P.A. and Coquart, L. and Maisonnave, E. and Moine, M.-P. and Terray, L. and Valcke, S. }, title = {Decadal prediction skill using high-resolution climate model}, year = {2017}, number = {9-10}, volume = {49}, pages = {3527–3550}, doi = {10.1007/s00382-017-3528-x}, journal = {Climate Dynamics}, pdf = {http://cerfacs.fr/wp-content/uploads/2017/11/GLOBC-Monerie_et_al_CLIMDYN_2017.pdf}}

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JOBS OFFERS

New job vacancy at Cerfacs: Research Scientist in Computational Fluid Dynamics for Modeling Environmental and Industrial risks

 

Main objective of the job Cerfacs carries out research in the field of environmental modeling for evaluating risks and monitoring natural...Read more


High Performance Computing

 

Contexte : Le Cerfacs co-développe des codes de simulation numérique dans les domaines de la combustion, de l’aérodynamique, de...Read more

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