General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DES-24-0135
Thesis topic details
Category
Engineering science
Thesis topics
Space-time domain decomposition method for incompressible flows, with a view to parallel computing
Contract
Thèse
Job description
Fluid flows in nuclear reactor cores are highly turbulent and their numerical simulation is particularly demanding in terms of computing resources. Computational codes are therefore based on massive parallelism, which can take several forms. The first level, used in the TrioCFD code developed by CEA's Energy Division, consists of accelerating the resolution of the linear systems resulting from the discretisation of the equations, time step by time step. The space-time domain decomposition (DD) constitutes a second level of parallelism, the study of which is proposed in this thesis. By dividing the computational domain into sub-domains, the principle is to transform the physical problem into a set of decoupled sub-problems of smaller sizes, which can be solved in parallel over the entire time interval. Space-time data is then exchanged on the interfaces between sub-domains and the process is repeated until convergence towards the solution of the global problem. Finally, a third level consists of coupling the DD method with a time-parallel algorithm, which divides the time interval into temporal sub-windows and uses a prediction/correction strategy, with the costly correction phase being performed in parallel on each temporal sub-window. The proposed thesis, which will mainly be pursued at the CEA Saclay, has a theoretical aspect on the analysis of these methods when applied to the Navier-Stokes équations and a practical aspect for an efficient implementation in the TrioCFD code, by optimising the algorithmic of these different steps and their coupling.
University / doctoral school
Ecole Doctorale Galilée (Galiléé)
Paris XIII
Thesis topic location
Site
Saclay
Requester
Position start date
01/10/2024
Person to be contacted by the applicant
OMNES Pascal pascal.omnes@cea.fr
CEA
DES/DM2S/SGLS/LCAN
CEA/Saclay DES-ISAS-DM2S-SGLS
91191 Gif sur Yvette Cedex
01.69.08.43.57
Tutor / Responsible thesis director
OMNES Pascal pascal.omnes@cea.fr
CEA
DES/DM2S/SGLS/LCAN
CEA/Saclay DES-ISAS-DM2S-SGLS
91191 Gif sur Yvette Cedex
01.69.08.43.57
En savoir plus
https://triocfd.cea.fr/