Cerfacs Enter the world of high performance ...

The 27 March 2019 at 14h00

PhD defense : Mathieu CATCHIRAYER -“WMLES, wall-model, boundary layer, turbulence, turbomachinery”

 |  JCA CONFERENCE ROOM, CERFACS, Toulouse, France |  


In the light of the energetic challenges faced by aeronautical engine manufacturers, a better understanding of the flows governing their gas turbines is required. Numerical simulations through Large-Eddy Simulation (LES) approach is well suited to this quest for innovation. However, its computational cost is prohibitive in the case of boundary layers at Reynolds numbers encountered in aeronautics. One way to tackle this limitation is to use a WMLES (Wall-Modeled LES) approach: near-wall turbulence is modeled thanks to a wall-model. Nonetheless, this approach is still an open issue for industrials flows. Therefore, a new suited wall-model is developed in this study: the iWMLES (integral WMLES). It is analogous to the von Kármán-Pohlhausen integral method for laminar flows: the velocity and temperature profiles are parameterized, and unknown coefficients are determined by matching boundary conditions obeying the integral boundary layer equations. It allows compressibility, temperature and pressure gradient effects to be taken into account at a low computational cost. Parameterized profiles are based on the usual logarithmic wall functions with corrective terms to extend their range of applicability. Instead of solving a set of differential equations as standard numerical wall-models, a simple linear system is solved. The proposed wall-model is implemented in a finite-volume cell-centered structured grid solver and assessed on academic flows. First, adiabatic and isothermal plane channel flows at several friction Reynolds and Mach numbers are simulated. In all cases, mean profiles, wall fluxes, and turbulent fluctuations are in agreement with Direct Numerical Simulation (DNS) data. Especially, the supersonic flow cases show that the iWMLES has a wider domain of validity than standard wall-models. Second, an experimental boundary layer under adverse pressure gradient is considered. The iWMLES is shown to predict correctly the one-point turbulence statistics. Finally, the iWMLES is applied to an axial compressor stage, demonstrating its robustness, and results are compared with wall-resolved LES data.            


Éric LAMBALLAISUniversité de Poitiers (France)                 Referee
Nicolas GOURDAIN    ISAE-Supaero, Toulouse (France)           Referee
Sébastien DECK  Université de Montpellier  (France)          Member
Franck NICOUD  Université de Montpellier  (France)          Member
Maria Vittoria SALVETTI  Università Di Pisa  (Italy)                          Member
Pierre SAGAUT  Université Aix Marseille   (France)            Advisor
Jean-François BOUSSUGECERFACS, Toulouse (France)                   Co advisor
Dimitrios PAPADOGIANNIS    SAFRAN TECH Châteaufort (France)       Invited member

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Thierry Poinsot officially entered the French Academy of Sciences

CERFACS |  8 November 2021

Thierry Poinsot officially entered the French Academy of Sciences on October 12. See presentation here :Read more

The AVBP code from CERFACS at the heart of for PRACE projects from the 23rd call

CERFACS |  30 September 2021

Cerfacs is involved in three PRACE projects of the 23rd call for which hour allocation runs from 01/10/2021 to 30/09/2022. Researchers from ECL/LMFA UMR5509 (Ecole Centrale de Lyon) and IMFT (UMR 5502) laboratories have earned projects entirely based on the use of the LES solver developed by Cerfacs AVBP and involve the support of experts from the CFD and COOP teams underling the importance and effectiveness of collaborations between French labs and Cerfacs. Alexis Giauque from ECL/LMFA UMR5509 (Ecole Centrale de Lyon) has obtained not only one but two PRACE projects! The first project LESFAN (RA0101, 30 000 000 CPU hours on Irene/Rome TGCC) is based on the use of AVBP in the turbomachinery version to study the generation of noise by a fan of a real airplane engine. The second, PRACE-EDGES (RA0101, 40 000 000 CPU hours on Irene/Rome TGCC) focuses on LES modeling of dens gas in complex geometries. To do so, the LMFA Team has developed advanced thermodynamic closures in AVBP allowing the direct simulation of such flows. Laurent Selle from IMFT (UMR 5502) has received CPU hours for the GASTON project (RA0061, 30 000 000 CPU hours on Marenostrum BSC) which aims to study the structure of hydrogen flames in porous materials. For this, IMFT and Cerfacs will perform coupled simulations considering the reactive flow with AVBP as well as the conduction in the porous medium with AVTP which is known to play an central role in the flame stabilization process. Carlos Perez Arroyo from IMFT (UMR 5502) received 16 Mh CPU hours on Joliot-Curie Skylake partition to support his project WONDER.Read more