Cerfacs Enter the world of high performance ...

@ARTICLE{AR-CFD-21-83, author = {Carmona, J. and Odier, N. and Desjardins, O. and Cuenot, B. and Misdariis, A. and Cayre, A. }, title = {A Comparative Study of Direct Numerical Simulation and Experimental Results on a Prefilming Airblast Atomization Configuration}, year = {2021}, number = {8}, volume = {31}, pages = {9-32}, doi = {10.1615/AtomizSpr.2021037399}, journal = {Atomization and Sprays}, abstract = {Liquid injection systems play a key role in the control of flame stability and reduction of pollutant emissions in aircraft engines. However, the disintegration process of the liquid fuel is not completely understood. In that context, direct numerical simulations can be helpful but tend to be very costly. Indeed, they require high spatial resolution to accurately capture complex phenomena such as liquid-gas interface instabilities and primary atomization process with liquid bags, ligaments, and droplets formation. This paper presents a computational study of a prefilming atomizer where relevant di-mensionless parameters are chosen to reproduce realistic conditions while limiting CPU cost. The experiment under study is an academic configuration from KIT-ITS in which a liquid film is injected along a prefilmer plate surrounded by high-speed air flow. The simulation has been performed with the incompressible solver NGA using a volume of fluid method coupled with a piecewise linear interface calculation technique for interface reconstruction. Qualitative and quantitative analyses are carried out and show very good agreement between simulation and experiment. The main physical phenomena such as film instabilities, liquid accumulation process at the prefilmer edge, and primary breakup mechanisms are well recovered by the simulation and in agreement with the experiment. A consistent method to compare both the experiment and the numerical simulation based on frame analysis is developed to extract the droplet diameter distribution. The resulting size distribution evaluated from simulation is shown to be in good agreement with experimental data validating our proposed methodology to reduce computational cost. }, keywords = {Atomization, prefilming airblast, liquid film, ligament-breakup, bag-breakup, droplet size distribution, direct numerical simulation, volume of fluid}, url = {https://www.dl.begellhouse.com/pt/journals/6a7c7e10642258cc,665548b84602ecc4,5d21940029f6ebd3.html#}}

@ARTICLE{AR-CFD-21-74, author = {Cazères, Q. and Pepiot, P. and Riber, E. and Cuenot, B. }, title = {A fully automatic procedure for the analytical reduction of chemical kinetics mechanisms for Computational Fluid Dynamics applications}, year = {2021}, volume = {303}, pages = {121247}, doi = {10.1016/j.fuel.2021.121247}, journal = {Fuel}, abstract = {A new software called ARCANE has been developed to address the broad need for compact, computationally efficient chemical models for reactive flow simulations. Based on a new, fully automatic and optimised multi-step reduction methodology, ARCANE's purpose is to provide a convenient and more accessible framework for the analysis and reduction of chemical kinetic mechanisms in the general context of combustion chemistry. The capabilities and performance of the methodology are demonstrated through 3 case studies. First, a classical methane/air system with and without nitrogen/oxygen chemistry is studied as a benchmark. The framework is then applied to a kerosene/air mechanism with a multi-component fuel formulation, showing the ability of the fully automatic method to handle complex chemistry. Finally, the generality of the approach is confirmed by developing reduced chemical models for a hydrocarbon steam cracking process.}, keywords = {Chemical kinetics reduction, ARCANE, Analytically reduced chemistry}}

@ARTICLE{AR-CFD-21-82, author = {Lamidel, D. and Daviller, G. and Roger, M. and Posson, H. }, title = {Numerical Prediction of the Aerodynamics and Acoustics of aTip Leakage Flow Using Large-Eddy Simulation}, year = {2021}, number = {3}, volume = {6}, pages = {article number 27}, doi = {10.3390/ijtpp6030027}, journal = {International Journal of Turbomachinery, Propulsion and Power}, abstract = {A Large-Eddy Simulation of the tip leakage flow of a single airfoil is carried out. Theconfiguration consists of a non-rotating, isolated airfoil between two horizontal plates with a gap of10 mm between the tip of the airfoil and the lower plate. The Mach number of the incoming flow is0.2, and the Reynolds number based on the chord is 9.3×105. The objective of the present studyis to investigate the best way to compute both the aerodynamics and acoustics of the tip leakageflow. In particular, the importance of the inflow conditions on the prediction of the tip leakage vortexand the airfoil loading is underlined. On the other hand, the complex structure of the tip leakagevortex and its convection along the airfoil was recovered due to the use of a mesh adaptation basedon the dissipation of the kinetic energy. Finally, the ability of the wall law to model the flow in the tipleakage flow region was proven in terms of wall pressure fluctuations and acoustics in the far-field.}, keywords = {Large-eddy simulation, fan noise, tip leakage flow, tip clearance noise}, pdf = {https://cerfacs.fr/wp-content/uploads/2021/07/Lamidel_AR-CFD-21-82.pdf}}

@ARTICLE{AR-CFD-21-73, author = {Villafana, W. and Petronio, F. and Denig, A. and Jimenez, J.M. and Eremin, D. and Garrigues, L. and Taccogna, F. and Alvarez Laguna, A. and Boeuf, J.P. and Bourdon, A. and Chabert, P. and Charoy, T. and Cuenot, B. and Hara, K. and Pechereau, F. and Smolyakov, A. and Sydorenko, D. and Tavant, A. and Vermorel, O. }, title = {2D radial-azimuthal particle-in-cell benchmark for E x B discharges}, year = {2021}, doi = {10.1088/1361-6595/ac0a4a}, journal = {Plasma Sources Science and Technology}, abstract = {In this paper we propose a representative simulation test-case of E x B discharges accounting for plasma wall interactions with the presence of both the Electron Cyclotron Drift Instability (ECDI) and the Modified-Two-Stream-Instability(MTSI). Six independently developed Particle-In-Cell (PIC) codes have simulated this benchmark case, with the same specified conditions. The characteristics of the different codes and computing times are given. Results show that both instabilities were captured in a similar fashion and good agreement between the different PIC codes is reported as main plasma parameters were closely related within a 5% interval.The number of macroparticles per cell was also varied and statistical convergence was reached. Detailed outputs are given in the supplementary data, to be used by other similar groups in the perspective of code verification.}, keywords = {benchmark, modified two-stream instability, electron cycloton drift instability, plasma-wall interactions, ExB discharges, particle-in-cell}}

@ARTICLE{AR-CMGC-21-75, author = {Saint-Martin, D. and Geoffroy, O. and Voldoire, A. and Cattiaux, J. and Brient, F. and Chauvin, F. and Chevalier, M. and Colin, J. and Decharme, B. and Delire, C. and Douville, H. and Guérémy, F. and Joetzjer, E. and Ribes, A. and Roehrig, R. and Terray, L. and Valcke, S. }, title = {Tracking Changes in Climate Sensitivity in CNRM Climate Models}, year = {2021}, number = {6}, volume = {13}, pages = {e2020MS002190}, doi = {10.1029/2020MS002190}, journal = {Journal of Advances in Modeling Earth Systems}, pdf = {https://cerfacs.fr/wp-content/uploads/2021/06/Globc-AR-Terray-J.Adv_.Model_.EarthSyst-21-75.pdf}}