CERFACS CERFACS Scientific Activity Report Jan. 2010 – Dec. 2011

COUPLING TOOLS AND HPC CLIMATE MODELING
2010’s reflexion. Financial support is provided by CERFACS and ONERA completed by projects as the
FLUI project COSMOS+.
More and more users would like to couple commercial codes like Fluent or Abaqus with OpenPALM.
The standard use of OpenPALM imposes to the users to have access to the code sources they want to
couple, which is usually not possible with commercial codes. In general, with these computation codes a
breach is nevertheless possible by calling routines developed in the form of dynamic library (*.so). New
functions allowing these codes to be dynamically connected to the coupler have been developed using MPI
functionalities. More portable methods are under evaluation like the socket mechanism. This last protocol
is a very promising path and will allow to couple solvers that run on distinct architectures connected on a
network.
In parallel the OpenPALM team has granted the maintenance of the previous versions and has provided
extensive user support, including training sessions (at least 4 per year) both on the use of the coupler itself
and on its application to parallel coupling and data assimilation suites ([CC6]).
Today, the OpenPALM coupler has proven to be a flexible and powerful parallel dynamic coupler with
application domains extending far beyond data assimilation. The user community is constantly increasing
and the software is ceaselessly evolving to deal with new functional requirements and new hardware
technologies. For more information, one can consult the OpenPALM website :
http ://www.cerfacs.fr/globc/PALM WEB/index.html
3.2 Usage of OpenPALM
3.2.1 Data assimilation with OpenPALM
As a data assimilation framework, the OpenPALM coupler is used in the operational suite of the
MERCATOR ocean forecasting system and for research purposes by the “Research and development” teams
(selected by the GMMC) and by DRM. CNRM, CNES, IPSL and LA use OpenPALM in the French project
ADOMOCA for atmospheric chemistry data assimilation. CNRM also takes advantage of OpenPALM to
build a hydro-meteorological data assimilation suite based on the Safran-Isba-Modcou chain. In the same
field the SCHAPI uses OpenPALM to assemble two data assimilation suites in hydrology and hydraulics for
the river floods forecasting. The hydraulic data assimilation suite is currently being tested in their real time
operational forecasting system, while different research actions, including a PhD thesis constantly improve
the suite.
EDF used OpenPALM in the ADONIS project to design a data assimilation methods in neutronics
simulation that was eventually implemented within the prescribed operational environment based on
Salomé. From this experience and from the results obtained at SCHAPI, another research department in
EDF, the LNHE got interested in the use of OpenPALM for hydraulics application, namely for a data
assimilation suite for the complete 3D modelling of the salinity evolution in a salted water basin where
fresh water is discharged from production plants.
3.2.2 Code coupling with OpenPALM
As a code coupler, OpenPALM has started to be used at CERFACS by the CFD TEAM in RANS (N3S-
Natur) and LES (AVBP) coupled applications ([17]). Having proven its efficiency, it is now spreading in the
scientific and engineering community. Among its users, we list SNECMA (DMA and SPS) and ONERA
which both use OpenPALM in CFD coupled applications. The CFD-Team of CERFACS uses intensively the
OpenPALM coupler for multiphysics and multi-composant simulations [7, 8, CC3, 21, 28, 27, 29, 31, 30].
The main codes of the CFD-Team are interfaced with the coupler (AVBP, AVTP, PRISSMA and elsA).
CERFACS ACTIVITY REPORT 105