salome_cfd: An HPC framework for thermalhydraulics and multiphysics powered by the open-source Computational Fluid Dynamics Toolbox code_saturne

\nEDF R&D lab Chatou, Fluid Mechanics Energy and Environment department (MFEE), has been developping an HPC oriented Computational Fluid Dynamics toolbox since the late 1990s. This toolbox is based on the open-source Computational Fluid Dynamics (CFD) and multiphysics solver code_saturne. It has a proprietary extension, neptune_cfd, which is a Computational Multiphase Fluid Dynamics solver dealing with multi-phase flows. After a brief overview of code_saturne and neptune_cfd architecture and HPC capabilites, the present paper will focus on the effort made at EDF R&D to harness HPC clusters for thermalhydraulics at an industrial scale. This is made available by codes built from the start with massively-parallel architectures in mind, thus leading to highly scalable solvers which are able to handle tens of billions of cells. User-friendly access and interoperability are pivotal for engineers to take advantage of these HPC capabilities. Among common applications requiring HPC resources, a focus is first made on frontier scale simulations, then on parametric studies and uncertainty quantifications experiments, where a twolevel parallelism is needed : a parallel Design of Experiment evaluation drives computations themselves (massively) parallel.\n