WIXLIB

N95- 28752TUNEDGRIDGENERATIONArmin WulfICEMWITHand VedatCFDBerkeley,ICEMCFDAkdagEngineeringCA 94704ABSTRACTICEMCFDis a CAD basedtured, unstructuredefforts haveunstructurederationmaticpackageand unstructuredthat opmentbeen spent to extend ICEM CFD's multiblockstructuredand hexahedralgrid generationcapabilities.The modules added are: a parametricgrid gen-moduleversionobjectsgrid generationtetrahedraland a semi-automaticof the hexahedralin rectilinearthe procedureshexahedralgrid generationgrid generationenclosuresmodulehas been developed.used will be described,Theseand examplesmodule.for aroundA fullyauto-a set of predefinedmoduleswill be presentedandwill be discussed.INTRODUCTIONThe abilityto accuratelytions is becominggridscreate a computationalincreasinglycan be employedtools for creatingimportantto treat complexgeometriesgrid aboutin the analysisgeometricor importingExistingmethodserationgeometryfrom variousare generallyin orderfor overICEMCFD computationalCFD embodiesCADsystems.25 differentconfigurafull CADComputationalCFDflow solversgrid genlitverytime consuming.Current codesalso require high level of userexpertiseWithICEMcomplexfor , includingboundaryconditionscan be generatedand structuralanalysis codes 1. (Figure1).structuredgeometricallyto achieveGEOMETRYANALYSISCODESopti-mal usage. Since the rapid constructionof suitable multiblockstructuredcomputationalstill one of the pacingCFDapplications,tionalityCFD.additionalhas beenTheygrids isissuesaddedare ICEMinfunc-to ICEMCOMAKforparametricmulti-blockmesh generation and ICEM HEXA for semiautomaticgeneration.hexahedralIn addition,Figuremeshthe fully automatichexahedralI:Positioningof lCEMgeometr3, andanalysisgrid generationCFDbetweencodes.modulecalledtheICE-PAK will be presented.ICEPAKhas been developedInternational(fdi) 2 to support thermal managementin coorporationwith Fluid Dynamicsof electronicenclosures.For ICEPAKfully automaticrestricted.the geometrygrid generationis possible,because477representationis

PARAMETRICICEMCOMAKICEMCFD'susingCOMAKto get a meshGRIDis a parametricstructuredGENERATIONmulti-blockgrid generation(COnfigurationof the sametopologygrid CEMCOMAKtool whichis an extendedof a givenconfigurationthe meshit is possiblewith geometric. USINGto replaydifferences.the constructionIt offersoptionis created,processtwo modes;ofin orderthe Specifica-Geometrywith anySystemJdefinitionof aSurfaceGeometryconfigurationInitial StepI-I Parametric Grid GenerationREAD NEWSURFACE OBJECTSCreateObjectsSurface .of BL OCK DECOMPOSITIONAUTOMATIC REGENERATIONDecompositionDefine Block]Q:CommendSaveEdit File ]WITHGENERATEBOUNDARYMESHCONDITIONStl,Generate MESHwith BoundaryFigureConditions2: Structuref'ICEMCOMA478K, the parametricgridgenerator

tion Modeand the Replayhim to interactivelyare storedobjectent. The boundaryefficientIn Figuretradeor Pro-EngineerusingDuringthe initialinput in IGESthe user has a set of toolsMode,geometricwhenentities.the user wantsit is only necessaryto breakallowingThe user'sto createthe objectactionsa mesharoundgeometryintoare set-upautomatically.of ICEMCOMAKfrom Parametrica parametricfeaturesallowone to performveryis shown.TechnologyCADsystemsCorporationsuchas I/EMSInte-are modelersfromthat can createapproach.step or the specificationformatThesestudies.2, the structuregeometriestopology,Modeand manageThen the user can replay the commandsto create the new multi-blockstructo the new CAD geometry,where sets of geometricalentities can be differ-conditionsgeometricgroupfile. In the Replaywith the sameparts like the original.tured mesh associatedIn the Specificationmanipulate,into a commanda differentgraphMode.create,to the ICEMmode,COMAKthe geometryenvironment.from the user'sCADsystemThe first step is to put surfacesisintoobject groups. The user then composesthe computationalblock structure.During this operationthe session commandsare recordedin a commandfile. The file created is saved. After the pointsalongblockedgesare distributed,the analysis are also createdformat of choice.To performthe parametricwith geometricdifferences,the computationalduringthis session.meshcalculationgrid is created.The boundaryUser then translatesthe meshfor a similargeometryand namesthe objectsthe user goes backconditionsforinto the flow solverwith the samein the newtopologygeometrybutwiththe same object names. After the new IGES file is created, the ICEM Manager grabs this IGESfile and writes the CAD data into the object databaseand initiates ICEM COMAK.COMAKreadsthe new objectcomputationalmat. The replaybatchmodemodeManagerregenerateswith the new geometrycan be treatedon modifiedThe ICEMgraphicalfiles and automaticallytopologythe computationaland translatesas a continuousthe meshgrid by updatingtheinto the flow solverfor-loop for computationalgrid generationingeometries.is writtenuser interfacein TCL/TKapplications.3 a programmingsystemIt is an easy to use scriptingfor developinglanguageand usingfor controllingandextendingapplications.The followingsample script illustratesthe executionof a series of commands in the ICEM Managerto support the automaticreplay modeasit is describedabove. In thisexampleit createsan input for the structuralshowsto run a complexanalysiscodeANSYStems, Inc.# This script# The actions# 1. Translates# andthehowit performsare:two IGES files intoIGES files areknownDDNon each# objects.# 3, Run a Comakto automatically# To makeanscriptANSYSthis script# -/,iceman initparts,fromThe nameswithintheof thesepartspart.whichextractsgeneratea set of winglinefile:## if [file existsusermanager.beforehand.# 2 Run a GPL program# 4. Writecommandappscript,tcl]( sourceuserappscript.tcl}479in yourfromSwansonAnalysisSys-

## The rest of this file is theIt shouldbein thecontentsdirectoryof customyouproc user app script{what} (global env ddn pathconfnameputpathglobal partnames2u pathparts/*ansys out-objects.unselect partcatch (exec/bin/rmobjects/ confname/ geoname/*)directory\directoryd 1foreach if (glob iges/*) [# Convert the part to tGES.set dn (file tail (file rootnameSill]set command- env(ICEM ACN)/iges/iges posti iges/ pfo parts/ dnI iges tist togit yes d directive tmp"runcom commandtges listif [string match *name" Sdn] { lappendnames dn }file that runs the GPL programname dn\update partlistif [( what "all") I I ( what "output")}{# Convert the structureddomains into an unstructuredset dams (glob mulcad/ confname/ geoname/domains/*]set topoflte mulcad/ confname/topology/topo mulcad outset outfile place/domains/struct mergeruncom " s2u path -t topoflle -o ouffile doms"and then exits.# Now run the ansys converter.set topofilemulcad/ confname/ geoname/bocoset ansys mulcad/ confname/ geoname/transfer/ANSYSruncom " ansys output path-dam outfile -b bocofile partname\"sn:linfomsg\"" 0 0makemenumake entrymake entrymakeentrymake entry}k 1# Clear out the old domains.set dams [glob -nocomplainmulcad/ confname/ geoname/domains/"]if (Sdoms ! ""} {eval exec/bin/rm-f doms )}typein to Mulcad"Doneto performare the commandsthe indicatedone. ansys"with conversion."# These lines create# Now move all the parbs to the Comak directory.foreach pf [glob parts/") [if (string match *name* pf) continueexec/bin/cpSpf objects/ confname/ geoname# user would*)}}}d 1if0 {if {( what "all") I I ( what : "comak")}{set extras ""# Now run the Comak job. These key sequencesthe5 extras]}}update partlist"ICEM 3.1 GRAPHICS"#1.I.12.].)set extras {I 6 5.2.).) I.) Y 10,3 Y Y n ) 11.2. I. 12,),5.3}app mulcad extrasset restart [open .restart.trapw]puts restart "F.5.13.5.3. [pwd]"puts restart "F.513.3kim1 gpt"puts restart "F.4.7.y"close restart}pn:\"]}if {( what "all") II ( what : "comak")}(unselect partcatch {exec/bin/rm-f (glob mulcad/ confname/ geoname/parts/testlupdate partlistm 1set partnameTEST1set sheetnametd 1foreach pf Snames{# Run the GPL program.set part partfileparts/ pfif { partname "'} { error "No part"set command" ddnpath db partsi .restart.tmp(get ddn defaults]"runxcom USER APP GPL commandmulcad/ confname/ geoname/parts/testl}))a DDN command-f [globset key (send keyboard eventsapp mulcadexec/bin/rm-f Skey# Convert all the parts in the iges directoryto DDN parts.# If any of them have "name*in their fllename,run them through# the gpl program.set names ""# MakeSxx 0]updatepartltst m 1set partnameTEST1set sheetname1# Set up the IGES directivefile,exec/bin/echo*CONVERT, NAME directive trapexec/bin/echo"define,CREATE310 PART I directive trapupdate partlistextras 0index})update partlist)}{if (Spi "') {eval exec/bin/tin-f Sp parts/.ddnobjects/ confname/Sgeoname/.ddn52]]Run the key.cmd file. }nnnDon'tmodify parameters.))yExit comak. }03yy)Updatetopology.}1253yMesh generation.})))Back to the top. }96yExit mulcad}appendif {( what "all*) II ( what "prepare")}(# First remove all the existing DDN parts and the Comakset p [glob -nocomplain{({({{[whichthatactions480a new menuuser appuser appuser appuser appuser appand add the above"USER Application""Whole script ."Prepare objects ."Run Comak ."Write output .commandto the menu""user app scriptall .user app scriptprepareuser app scriptcomak .user app scriptoutput .

Figure3 illustratesthe applicationof ICEM COMAK to full airplanevolumegrid configurations4.Usingthe specificationmodethe volumegrid is calculatedfor theA320 aircraft.The commandfile is replayedtocreatethe similargrid for theA330 aircraft.Noticethe differencesin the sizesoftheengineandthe fuselagealsothedistancesof the pylon from the fuselageaswell asthe impacton the createdgrids.A320 Grid Using Specification ModeFigure3: Using ICEMCOMAK,generationof grid forSEMI-AUTOMATICICEM HEXAblock ckstructurea volumeor, alternatively,Blocksor externalICEMcanwith completeof the underlyingCADany other CADreolithography)The followingmulti-initial-to the underby the systemindependencefrom the orientationof the patchesis an examplein FigureusingIGESor other translatorsurfacemeshescontrolbound-formats.in PATRANtrimmed NURB surfaceCAD tool or translatedSurfaceformatmeshesin STL (Ste-can also be inputas a sur-generation.of the grid generation4. This configurationand controllingand patchgeometry.or triangularfor meshcal port for chemicalfor inspectionsystemformatface representationtank as shownadjustedbe generatedInput to ICEM HEXA is CAD geometry,in the form of NURB surfaces,and NURB curves. CAD geometryis either created using ICEM CFD'sfromfor creatingwill automaticallycan be interactivelyO-GridsHEXAmesherHEXAand automaticMesh sizes can be defined on the object surfaces or individuallyon the edges usingoptions. The grid is projectedonto the underlyingCAD geometrywith minimumuser interaction,ariesthe initialgeometry.automatically.edge meshingGRIDcomputationalvolumegrid for A320the A330 (Courtesyof Aerospatiale).is an object based semi-automatedmeshes or unstructuredhexahedralThe user can defineize the blockA330 Grid Using Specification Modeand two petrudingthe chemicalprocesscontainscylindersprocessfor a generican inlet, an exhausttakingto the tank.placeinsideThesechemicalport,cylindersthe tank.processinganotherEachcylindri-are utilizedof thesecylindersare connectedto a smaller cylinderswhich they connect to pressureregulators.Sincethis configurationcontains many cylinder T-connections,it producesa moderatelycomplex blockdecompositionstrategyfor any grid generationsystem.481

Control portExhaustportControl portTankInle/Figure 4." The chemicalprocessingtankFigure 5." Block decompositionThesystemNexttheusedfor gridverticesareautomaticallyblocksgenerationfit to thecan be associatedverticestheinitialareare movedfit, blockssplitaregeometryto ngalsoAfterselected.withinteractivetakenthe curves.are splitthefromTheto providestrategyas tructureovertheTheAfterthatblockedgeswillareasin Figuresuchbeedgesof theandblocksthe associationis shownthe critical5.blocksof blocks,manipulation.the CADblockingin Figureis done,6. Afteras thecontrol