SALOME7THE OPEN SOURCE INTEGRATION PLATFORM FOR NUMERICAL SIMULATION

salome-platform.org

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DEVELOPMENT FACT SHEET

Project kick off 2001

Development 20 personsteam

Licence LGPL

Distribution one major version every 2 years, and maintenance versions every 6 months.

Bugtracking 500 fixes and improvments /year.

Verification 4000 tests. & Validation

Users 300 users at EDFand CEA, 4000 users overthe world, 40000 downloadsin year 2012

The SALOME software platform is an open framework that can integrate scientific solvers for

modelling various physical domains and realize a wide range of computing simulations. In the context

of CEA and EDF, the physical systems are typically the industrial equipments of the nuclear production

plants, with as primary concern the design of new generation reactors, the nuclear fuel management,

the reliability and safety of the installations, or the equipments ageing for an optimized life cycle

management. The challenges are to analyse the behaviour of the systems with sufficient accuracy and

performance to aid the decision making on industrial questions. SALOME comes natively with CAD

modelling, mesh algorithms, 3D visualization and advanced functions for simulation data processing.

DOWNLOAD THESALOME PLATFORMThe SALOME platform can bedownloaded from the web site:http://www.salome-platform.orgfor several LINUX distributions andWINDOWS. The site provides tuto-rials, a forum section and gives ac-cess to user documentation andsource code under LGPL licence.

SERVICE AND SUPPORTEURIWARE and Open Cascade pro-vide a whole range of services forSALOME towards professional end-users including technical supportand specific training.

Support services are availablewithin a “à-la-carte” support pro-gram particularly suited for univer-sities and academic organizationsas well as for small or larger indus-trial companies:

Helpdesk support for expertneeds concerning a one-shottechnical issue, delivered by mailor by phone within a guaranteedtime frame.

Technical support for complexproblem solving that requires thehelp of a qualified engineer.

Expert consulting delivered onthe end-user premises by one ofthe SALOME expert.

Assistance to create SALOME extension modules or solver inte-gration.

Patch request for an immediateaccess to correction, bug fixingand intermediate certified re-leases.

For more details, consult:http://www.salome-platform.org/service-and-support/available-programs

KEY FEATURESThe numerical analysis of complexindustrial systems demands fromscientists and engineers to inte-grate most domains of physics likematerial science, solid mechanicsand structural dynamics, fluidsphysics and thermohydraulics, nu-clear physics and radiations, elec-tromagnetism. These domains canbe federated in one single simula-tion environment, the SALOMEplatform.

The main features of the SALOMEplatform are :

The design of the geometryrepresentation of physical sys-tems (CAD modelling) and its as-sociated discretized model(meshing functions for finite ele-ments or finite volumes solvers).

The ability to integrate do-main specific solvers intonormalized software compo-nents with standard interfaces tofacilitate the coupling of differentphysical domains.

The supervision of compu-tation workflows defined asgraphs of distributed softwarecomponents, including CADmodelling, domain specificsolvers and data processing com-ponents.

The analysis of simulationdata, in particular using visuali-zation of physical fields resultingfrom computation workflows.

In this context, a key point of theplatform is the usage of standarddata models to describe physicalconcepts for numerical analysis,and to ensure interoperability be-tween software components. TheMED data model for example isused to describe geometric meshesand physical fields.

MODEL OFDEVELOPMENTThe SALOME platform is activelydeveloped by CEA and EDF, two ofthe key actors in the domain of energy in France, and with the support of the EURIWARE/OpenCascade company, a leader in thedevelopment of software programsfor scientific modelling and com-puting simulation. This 12 years oldpartnership provides the SALOMEdevelopment project with a verycommitted and dedicated team inscientific computing, in particularfor specific applications in nuclearindustry.

Moreover, the SALOME platformdevelopment relies on the integra-tion of cutting edge third partysoftware programs, for examplethe commercial advanced and ro-bust meshing programs Mesh-Gems-CADSurf (formerly known asBLSURF) and MeshGems- Tetra (for-merly known as GHS3D) (by theDistene Company) and the PAR-AVIEW software including the VTK3D visualisation toolkit (by theKitware Company).

Recent efforts in the developmentof SALOME for parallel computa-tion have been supported bySystem@tic, Paris region systemand ICT cluster. This includes for ex-ample the projects IOLS, EHPOC,OpenHPC, ILMAB and OASIS.

Figure 1: Screenshot of thepublic web site of SALOME.www.salome-platform.org

SALOME7PLATFORM

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The SALOME platform provides a software suite to integrate domain specific

tools and realize dedicated solutions for simulation of physical systems.

For example, you can download from http://www.code-aster.org the

SALOME-MECA application that is the EDF simulation environment to

investigate solid and structural mechanics questions about equipments

ageing, reliability and safety of production plants. This application is a

software configuration that integrate the SALOME platform with the

Code_Aster solver and its computing environment.

A second example is PANTHEREV2,a numerical simulation applicationdedicated to industrial radiationprotection. The screenshot below il-lustrates the computation of theaverage dose rate in a nuclearpower plant (Figure 2).

Figure2: Evaluation of the average dose rate of radiation using the PANTHERE application (EDF/SEPTEN).

Figure3: PPGP application, at left: tree of a all elements of a steam generator, at middle: python accessto specific changes, at right: dialog box to edit values of a part of the steam generator

DEVELOPINGDOMAIN SPECIFICAPPLICATIONS

The following third example is aGUI interface for GENEPI+ codenamed PPGP and dedicated to theanalysis of steam generators. Ithelps the user to describe the gen-erators and its associated physicalproperties, and then manage thecomputing workflow from themeshing process to the data analy-sis and visualisation (Figure 3).

In this context, the SALOME plat-form is distributed with a QualityAssurance industrial process, inclu-ding a Verification and Validationactivity. The development teamprovides first level services and support to investigate the develop-ment of dedicated applications by third party projects.

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MODELLING THE GEOMETRYThe Geometry module (GEOM)provides a rich set of commands tocreate, edit, import or modify acomplex CAD model. The geomet-ric shapes may be designed interac-tively using the Graphical UserInterface (GUI) or the Text UserInterface (TUI) through pythonscripts. Each functionality of GEOMis available in TUI with facilities towork back and forth with thegraphical interface. This allows tobuild complex shapes or severalconfigurations of a shape with dif-ferent values of its parameters.

The module is powered by a geom-etry kernel based on the OpenCASCADE Technology which pro-vides a Boundary representation ofthe model (BRep) and maintainsthe topological structure requiredby the subsequent meshing opera-tions.

SALOME can exchanges geometrywith other CAD systems using for-mats as IGES, STEP, and BREP (theOpen CASCADE native format),(Figures 4 & 5).

MESHING THE GEOMETRYThe SALOME platform comes na-tively with a set of modules to cre-ate Finite-Elements representationsof the geometry of your system (e.g.SMESH module) and to refineparts of the mesh representationconsidering the solver specific re-quirements and the simulation ob-jectives (e.g. HOMARD module).

The Meshing module

The Meshing module (SMESH)transforms the solid shapes definedor imported in the Geometry mod-ule into finite-elements. TheMeshing module is used to createand edit the mesh data using a va-riety of different open source or 3rdparties meshing algorithms.

A concept of sub-meshes can beused to take into account the spe-cific features of the geometricalmodel. A different set of conditionscan be applied to each sub-mesh,for example to mesh with smallerelements some area of the shape,or to mesh an area with anotherkind of elements.

A complete toolbox enables theuser to verify the mesh quality andto perform local modification or ad-justment. Transformation opera-tions can be used to producecomplex meshes or compounds.

Mesh elements can be grouped tofacilitate the visualization and helpthe definition of initial boundaryconditions. These groups can beautomatically deduced from thecorresponding geometric groups,or generated using grouping crite-ria (named “filters” in SALOME).

As for the CAD process, the mesh-ing process can be entirely described into python scripts (TheText User Interface of SALOME) to handle complex studies or to ensure full reproducibility and parametrization of the simulationworkflow. (Figures 6 &7)

Figure 5: Representative Volume Elements generation for materialstudies (CEA/DEN).

Figures 6&7: Crack modelling for ageing analysis of a a piping system. Left: external view of thecomplete crack. Right: internal view of the detailled meshing strategy

MODELLING PHYSICAL SYSTEMS

The SALOME platform provides you with a whole set of modules

to create complex geometric models. This includes high level

meshing functionalities to prepare numerical models that fit the

solver requirements and simulation objectives, in terms of accuracy

and performance.

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Creating hexahedric models

The SALOME platform provides youwith specific mesh algorithms thathelp you with the creation of com-plex geometric models with hexa-hedric mesh representations. Thesemeshes are specifically required forsome numeric solvers, for examplestudies that involves fluid dynamicsolvers.

In this objectives, youcan use the HEXOTICplugin of the SMESHmodule. This plugin is awrapper for the commer-cial mesh programMeshGems-Hexa (formerlyknown as HEXOTIC) edited by theDistene Company. This functioncan create automatically a volumichexahedric mesh of a complexgeometry without any cubic parti-tion of the solids (Figure 9).

An alternative method is to use theHEXABLOCK module that helpsyou to define a topological descrip-tion isomorphic to the real geome-try and from which a volumichexahedric mesh can be automati-cally generated (Figure 10).

Figure 10: The topologic model of blocks (left), and the computed associated mesh (right) (CEA/DEN).

Optimization and refinement

The Meshing module comes with acompanion named the HOMARDmodule to perform specific meshadaptation to better fit the simula-tion objectives, in term of accuracyand performance.

To improve the quality of the simu-lation results, mesh adaptation of-fers an effective compromise,combining a fine mesh with a lowcomputational cost. The HOMARD®

module allows refinement andcoarsening techniques to adapt themesh, according to the numericalerror of the simulation.

HOMARD® is designed to operatein association with 2D/3D elementssuch as triangles, quadrangles,tetrahedrons and/or hexahedrons.The whole mesh can be conformalor not.

The selection of the elements to re-fine is made either by the localvalue of a field over the elementsand a threshold, by a group or by ageometrical zone. Splitting theiredges in 2 refines these elements.The transition between different re-finement zones is treated with spe-cial elements.

All HOMARD® instructions can beexecuted either using the graphicaluser interface or through thepython interface (Figure 8).

Figure 8: Mesh adaptation during the simulation of atunnel excavation (EDF/R&D).

Figure 4: Geometryof a stator formagneto-thermalanalysis (EDF/R&D).

Figure 9: Mesh representation ofa piping valve with automaticgeneration of hexahedron cells(EDF/R&D).

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The SALOME platform provides youwith a set of services to create asimulation workflow that connectsdifferent computation units andthen to execute the workflow on adistributed network of computersand HPC resources:

The YACSGEN program helpsyou with the generation of a SALOME component that inte-grates your specific solver or anyprocessing function.

The SALOME components arethe computation units of a work-flow designed with YACS.

The YACS module containsthe core set of services to com-pose the computation workflowas a graph of connected SALOME components.

This graph can be edited using agraphical user interface (GUI) orthe python Text User Interface(TUI) to handle complex work-flow into scripts.

The JOBMANAGER modulecan be used to define a compu-tation job (including either a sim-ple SALOME component or acomplete YACS workflow) andto drive the submission of the jobto a distributed set of computersor HPC resources.

The module can handle thebatch systems PBS, LSF, SGE,LOADLEVELER or SLURM througha normalized generic interface. Itcomes with a graphical user in-terface, but can be used at a pro-gramming level using a pythoninterface.

Based on these core services dedi-cated to the workflows edition andsupervision, you will find high levelservices to help you in the design ofa numeric experimental plan:

The PARAMETRIC modulecan be used to generate a para-metric simulation, by explorationof a specified domain of the sim-ulation parameters space.

Figure 11: Coupling of a neutronics model with a thermalhydraulics model for a nuclear safety study(CEA/DEN).

SUPERVISION OF COMPUTATIONWORKFLOWSThere is an increasing need for

multidisciplinary parametric

simulations in various research

and engineering domains.

Fluid-structure interaction and

thermal coupling are two

examples. The software

strategy in many contexts of

simulation (at least at CEA and

EDF) is to develop numerical

solvers dedicated to their own

domain, and then to execute

multi-domains simulation by

coupling the existing dedicated

solvers (Figure 11).

PROCESSINGSIMULATIONDATASETBeyond the processing and visuali-zation of meshes and fields data,the SALOME platform contains additional modules dedicated toadvanced data analysis :

Data assimilation and opti-misation environment, forexample to recalibrate the parameters of a model by com-parison of the simulation data toexperimental measures (moduleADAO)

Propagation of uncertain-ties in the simulation workflow,for example to evaluate the uncertainty on resulting data ofthe simulation considering agiven uncertainty on the inputparameters (module OPEN-TURNS).

Design numeric experimen-tal plans, for example a para-metric simulation by explorationof a specified domain of thesimulation parameters space(module PARAMETRIC).

PROCESSING FIELDSAND MESHESIn SALOME, the MED data modeldefines a normalized representa-tion to describe meshes of thegeometry and fields of the physicalvalues of the simulation. This datamodel is a key feature of the plat-form. It comes with a software im-plementation (the MED-file library)for file persistence and intercom-munication of simulation data be-tween components. SALOMEmeshing and visualization compo-nents propose interfaces with MEDformat to import or export data.Domain specific solvers that inter-act with SALOME are advised touse MED format for input and out-put files. This configuration leads toa high level of associativity betweenthe software components to buildsimulation workflows.

Based on the concepts from theMED data model, the MED-Coupling module of SALOMEprovides you with a full set of serv-ices for high performance data pro-cessing on meshes and fields.Extensively rewritten for SALOME 7,the module contains the data struc-ture to describe meshes and fieldsas C++ or python objects (MED-Coupling package). It provides a setof functions to manage the persist-ence toward the med file format(MEDLoader package), and func-tions to process the field data instandard algebraic operations(post-processing) or through inter-polation and localization algorithms(INTERP_KERNEL and REMAPPERpackages), for example to performfield projections from a mesh to an-other (Figure12).

VISUALIZATION OFSIMULATION RESULTSThe solvers interfacing with SALOME generate results that canbe analysed within the ParaViSmodule. This module has been de-veloped by integrating ParaView(third party software edited byKitware on basis of the VTK toolkit)into SALOME, and exposes all thefunctionalities of this award-win-ning post-processor tool.

A wide range of representations areavailable to the physicists to explorethe datasets: surface, volume,gauss points... The data can thenbe analysed by using one of manyfilters to extract significant data: clip,threshold, iso-surface, stream lines,elevation surface…

Quantitative information can be ex-tracted using the data analysistools: taking a selection of the data,histograms, 2D plots of time-plotsare easily obtained.

All these features can be animatedwithin the module to analyze time-varying data, sweep a cutting planethrough the dataset, or animate amodal analysis.

This module is fully scriptable inpython to create visualizations inbatch when necessary or to repeatanalysis on ensemble runs, and canuse visualization clustersto interactivelyanalyse largedatasets.

(Figure 13).

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Figure 13: Analysis of a Representative Volume Elementin material studies (CEA/DEN).

ANALYSIS OF SIMULATIONDATA

Figure 12: Projection of a fieldfrom a regular grid towards anunstructured mesh.

CONTACT US:Francis Kloss francis.kloss@cea.fr

Guillaume Boulant guillaume.boulant@edf.fr

Mikhail Kazakov mikhail.kazakov@opencascade.com @

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EDF R&D

1, avenue du Général de Gaulle,

92141 Clamart Cedex, France

www.edf.com

Open Cascade

Filiale d’EURIWARE, groupe AREVA,

1 place des frères Montgolfier

78044 Guyancourt, France

www.opencascade.com

Commissariat à l’Energie Atomique

et aux Energies Alternatives,

CEA-Saclay, DEN, DM2S,

91191 Gif-sur-Yvette Cedex, France

www.cea.fr