Gridgen经典培训教程.ppt

1,Inthissession:GridgenTerminology.GUIComponents.GridgenHelp.Building2DStructuredGrids.Building2DUnstructuredGrids.Tutorial:“2DBump:BasicSkills.”,GridgenTraining,Overview,2,WhatsanEntity?,Anentityisanyindividualelementthatmakesuppartofagridorgeometry.,GridgenTerminology,Domains,Blocks,Connectors,ExamplesofGridgenentities,3,Connectors,GridgenTerminology,Connectorsarethecurveentitiesthatdefineallgridedges.,Connectorscontainoneormoresegments.,Nodesmarkconnectorendpoints.,ControlPointsletuserdefinesegmentshape.,Connectorsaredimensionedbynumberofgridpointswithadistributiondescribinghowtheyareplaced.,4,Domains,GridgenTerminology,ADomainisasurfacegridentityboundedbyedges.,StructuredDomainsconsistsolelyofquadrilateralelements.,UnstructuredDomainsconsistsolelyoftriangularelements.,StructuredDomainshaveexactlyfouredges.,UnstructuredDomainsgenerallyhaveoneedge(moreiftheytheencompassholes).,Eachedgecontainsoneormoreconnector(s).,5,Blocks,GridgenTerminology,ABlockisavolumegridentityboundedbyfaces.,StructuredBlocksconsistsolelyofhexahedralelements.,UnstructuredBlockscanconsistoftetrahedral,pyramidal,and/orprismaticelements.,StructuredBlocksareboundedbyexactlysixfaces.,UnstructuredBlocksgenerallyhaveoneface(moreiftheyencompassholes).,Eachfacecontainsoneormoredomain(s).,6,Grids,AGridiscomposedofvolumeand/orsurfacegridblocks.,StructuredGridscontainonlyquadrilateralandhexahedralelements.,UnstructuredGridscontainonlytriangularandtetrahedralelements.,HybridGrids(suchasthatshownhere)containbothstructuredandunstructuredgridelements(quads,triangles,hexes,andtets)andcanalsohaveprismaticandpyramidalelements.,GridgenTerminology,7,Databases,InGridgen,databasesrefertocollectionsofgeometryinformationthatcanbeusedtodefinetheshapetowhichthegridistobebuiltandtypicallycomefromcomputeraideddesign(CAD)software:AnalyticcurveandsurfaceinformationfromaCADfile.Shelldiscreteunstructureddatabasesurfaceentity,generallyimportedfromstereolithography(STL)formattedfiles.Networkbilinear(non-slopecontinuous)databasesurfaceentity,generallyimportedfromPlot3Dformattedfiles.Ofcourse,databasesarenotnecessarytobuildgridswithGridgen,butareoftenneededforimportingcomplexgeometries.,GridgenTerminology,8,TheGridgenScreen,GUIComponents,VersionListsGridgenversionnumber,StatusTalliesnumberofgridentities,MessageProvidesinstructionsandpromptsfortextinput,TextInputEchoesdataenteredviakeyboard,BlackboardDisplayscontext-sensitivegraphicalandtabulardata(akaDiagnosticorBrowserwindow),CommandMenuListsGridgenCommands(akaButtonMenu),DisplayShowsgraphicalimageofgridanddatabase,9,TheMouse:Pan,Zoom,andPick,LeftMouseButton:PanPressandholdtheleftmousebuttontopanthemodelimageinthedisplaywindow.Whilepanning,themousecursorchangesto:,CenterMouseButton:ZoomPressandholdthecentermousebuttontochangethemodelimagessize,pushingthemouseawayfromyouzoomsoutwhilepullingittowardsyouzoomsin.Formicewithacenterwheel,thewheelcanberolledorhelddowntocontrolzoom.Ontwobuttonmice,zoomingisaccomplishedbyholdingbothbuttonsdown.Whilezooming,themousecursorchangesto:,RightMouseButton:PickPressandreleasetherightmousebuttontoselectcommandsfromthecommandmenuorpickentitiesinthedisplaywindoworbrowserlist.Whilepicking,themousecursorchangesto:,GUIComponents,10,SomeMouseOptions,GUIComponents,Thefunctionsoftheleftandrightmousebuttonscanbereversed,sothatleftisforpickingandrightisforpanning.ThiscanbedonebyselectingLeftPk.,Whendealingwithsmallergeometricentities,itmayalsobedesirabletoreducethemousesensitivityinpanning,zooming,androtatingthescreenimage.Thiscanbedonebyclickingonthebutton(moreclicks,lesssensitivity).,Youmaywishtochangesomeofthedefaultmousesettings.ThesecanbeaccessedbyselectingtheDisplayorDispsubmenufromGridgensMAINMENU.,11,ModelRotations,Y,X,Z,ScreenCoordinates,BodyCoordinates,GUIComponents,Gridgenhastwodistinctcoordinatesystems:screencoordinatesandbodycoordinates.Inadditiontopanning,zooming,andpicking,themousebuttonscanalsobeusedtorotatethemodelscreenimage.ThisisdonebycombiningtheleftandcentermousebuttonswiththeCtrlkey:Ctrl+leftmousebutton:screenxandyrotations.Ctrl+centermousebutton:screenzrotations.,12,ModelRotations(Continued),Formorepreciserotationcontrol,thefollowingnumpadkeyscanbeused:7rotatesaboutthexscreenaxis.8rotatesabouttheyscreenaxis.9rotatesaboutthezscreenaxis.NumLockrotatesaboutthexbodyaxis./rotatesabouttheybodyaxis.*rotatesaboutthezbodyaxis.Additionalrotationfeaturescanbeaccessedwiththefollowing“hotkeys”:PageDownusedwithanyofthex-y-zbody/screenkeysresultsina90deg.rotationaboutthecorrespondingcoordinatedirection.PageUpusedwithanymodelmanipulation,whetherbymouseorkeyboard,provides3xaccelerationoftheoperation.+andnumpadkeysreversethedirectionofakeyboardmodelrotation.Altusedwithanumpadmodelrotationgivesasingleincrement(3deg.)rotation.,GUIComponents,13,CommonlyUsedHotKeys,GUIComponents,Note:HotkeysforGridgencommandsareshownaspinkcharactersonthecorrespondingGUIbuttons.,14,FileBrowsing,SelectingInput/OutputfromtheMAINMENUopenstheINPUT/OUTPUTCOMMANDSsubmenufromwhich(inthisexample)theINPUTGridgenFILEsubmenuhasbeenselected.,TheBrowserWindowshowstheappropriatecontentsofthecurrentworkingdirectory.Themousecanbeusedtoscrollthroughandselectfromlist.,SelectingTypeinNameallowsyoutotypeinafilenameforimportorexport,whileTypeinDirletsanewworkingdirectorytobeset.,SelectingGotoDir(/inUnix)willprovidelistofavailabledrivestochangetoascurrentworkingdirectory,whileGotoDirOrigchangestheworkingdirectorybacktotheoriginaldirectorywhereGridgenwasopened.,GUIComponents,Oncefilehasbeenselected,Openisclicked.,15,FileBrowsing(Continued),UponenteringtheTypeinNamemode,thetextinputwindowwillechothefilenameenteredviathekeyboard.Oncethenameisentered,theEnterkeyonthekeyboardorOpenbuttonintheGUImustbeclicked.Theesckeycanbeusedtoexitfromtextinput.Noothercommandsormanipulationsareavailablewhileinthismode.Glyphexpressionsarevalid.,GUIComponents,16,GridgenFileNames,GridgenRestartFiles(.gg)containentiregridmodelsfromcontrolpointdefinitionsthroughboundaryconditionsettings.Theyonlyreferencedatabaseinformation.CompositeDatabaseFiles(.dba)store,inGridgensnativedatabasemodelformat,datafromalldatabasesources,aswellasdatabaseentitydisplayattributesandlayerinformation.,GUIComponents,17,GridgenHelp,GridgenHelp,Gridgenshtml-basedhelpcanbeaccessedfromvirtuallyanymenuwithintheprogrambyeithermouseclickingontheHelpbuttonorentering?Fromthekeyboard.ThishelpdocumentationisequivalenttotheUserManualandautomaticallyopenstothepertinentsectionrelatingtotheoperationormodecurrentlyinusewithinGridgen.Forexample,thewindowattheleftopenswhenhelpiscalleduponfromtheopeningI/Omenu.,18,Building2DStructuredGrids,Building2DStructuredGrids,Beginningwiththeairfoildatabasegeometrybelow,thehybridgridshownattherightwillbeconstructedusingGridgen,startingwiththe2Dstructuredblockatthetop.,19,The“Bottom-Up”GridgenProcess,Building2DStructuredGrids,SelectAnalysisSoftwareandMeshDimensionalityImportandManipulateDatabaseGeometryCreateSegmentsandConnectorsDimensionConnectorsandDistributeGridPointsAssembleDomainsAssembleBlocksSetupCFDAnalysisBoundariesExportandSaveFiles,20,SelectAnalysisSoftware,ThefirststepinanyGridgenprojectistheselectionoftheCFDanalysissoftwareandthedimensionality(2Dvs.3D)ofthemeshbeingconstructed.,IntheMAINMENU,AnalysisS/Wischosentobringupthecorrespondingcommandsmenu.,SelectAnalysisS/Wisthenclicked,whichbringsupthefairlylengthylistofsupportedCFDpackages.,Forthisexample,2Dandthedefaultgenericsolverwillbeselectedviamouseclicks.Oncetheseselectionsaremade,theNextPagebuttonisclickedtobringupthesecondhalfofthesupportedsoftwarelistsotheDonebuttonattheendofthelistcanbeselectedtoconfirmthechoices.,Building2DStructuredGrids,21,SetDefaults,Building2DStructuredGrids,Althoughnotessential,settingdefaultvaluesforsomeitems,suchasconnectordimension,cansavetimeduringthemeshconstructionprocess.,IntheMAINMENU,Defaultsischosentobringupthedefaultsmenu.Note:AnotherwaytobringupthedefaultsmenuistoselecttheDfltquickkey.,Theblackboardwindowshowsthecurrentdefaultsettings,e.g.,thedefaultconnectordimension(ConnDimens)is0.Thiscanbechangedbyselectingtheappropriatebuttonbelow.,Thisactivatesthetextinputwindow.Forthepresentexample,typein36andthenhitEntertostoreit.Theblackboardwindowwillshowthenewvalue.ClickDonetofinishsettingdefaults.,22,ImportDatabaseGeometry,Building2DStructuredGrids,Next,thedatabasefilecontainingtheairfoilgeometrywillbeimported.,IntheMAINMENU,Databaseischosentobringupthecorrespondingcommandsmenu.Note:Asanalternative,thefhotkeyonthekeyboardcouldbeused.,ImportisthenselectedtobringuptheINPUTDATABASEFILEsubmenu.,Thebrowserwindowshowstheavailabledatabase(.dba)filesinthecurrentworkingdirectory.Thedesiredfilecanthenbepickedwiththemouse(changingthenamefrompinktoblackincolor).ClickonOpentoreadthefileintoGridgenandthenDoneintheDATABASECOMMANDSmenutoreturntotheMAINMENU.,23,CreateConnectors,Building2DStructuredGrids,Itsnowpossibletostartbuildingtheconnectorsthatwillmakeuptheedgesofthegrid.Thefirstconnectorwillmatchtheuppercontouroftheairfoil.,IntheMAINMENU,Connectorsischosentobringupthecorrespondingcommandsmenu.,Sincetherearenoconnectorsyet,onlytheCreatecommandisavailableintheCONNECTORCOMMANDSmenu.SelectthistoopentheCreateConnectorsubmenu,Therearethreewaystobuildaconnector:individualcurvesegmentscanbecreatedandlinkedtogether,twoendpointscanbechosentoformaconnectorbetweenthem,oraconnectorcanbelaiddownuponadatabaseentity.Thislastoptionwillbepickedhere.,24,CreateConnectors(Continued),Theblackboardwindowshowstheavailabledatabaseentities.Themousecanbeusedtopickentitiesfromthislistordirectlyfromthedisplaywindow.Onceselected,thetableentryandtheconnectorinthedisplaychangefrompinktoblackincolor.,ClickingonDonecompletestheprocess.Becausethedefaultdimensionhasbeenset,thenewconnectorappearsinpalegreen(ifundimensioned,itwouldhavebeenbrightgreen).,Building2DStructuredGrids,25,CreateConnectors(Continued),Theremainingconnectorsneededtoformtheedgesofthemeshwillbecreatedwiththe2PointConnectorsoption.EachCPcanbeselectedfromthedisplayviathemouseorenteredviathekeyboard.Foreachnewconnector,Gridgeninitiallypositionsthedisplaycursoratthelastendpointofthepreviouslydefinedconnector.Here,allbutthelastconnectorhavebeendefined,andthedisplaycursorispositionedatthatconnectorstrailingendpoint.,Thetrailingendpointforthislastconnectorisalsotheleadingedgeendpointfortheconnectorappliedtotheairfoilsuppersurface.ItcanbeselectedbyrepositioningthedisplaycursorandusingbyPickingorbyenteringitscoordinatesviaKeyboard.Again,clickingDonefinishesthejob.,Asthisisthedesiredstartingpointofthelastconnector,itwillbeselectedviabyPicking.,Building2DStructuredGrids,2,0,0,2,1,0,-1,1,0,-1,0,0,26,CreateConnectors(Continued),Withthelastconnectorcompleted,clickonDoneCreatingConnsintheCREATECONNECTORmenu(orjusthitthecorrespondinghotkey,esc).Next,toseethegridpointdistribution,toggleConGPsinthedisplaymenu(orhitthehotkeycombinationac).Asshown,itsclearthattherearefarmoregridpointsalongthebottomedgethanthetop(sincetherearethreeconnectorsbelowtotheoneabove,buteachwiththesamedefaultdimension).Thishastobecorrectedbeforethedomaincanbebuilt.,Building2DStructuredGrids,27,(Re)DimensionConnectors,Building2DStructuredGrids,IntheCONNECTORCOMMANDSmenu,selectRedimensionGrids.Thiswillallowthetopconnectortobepickedinthedis-playwindowviathemouse,anditsnewdimensiontobeenteredviathekey-board.Inthiscase,106isthatnewdimension(whileeachofthethreebottomconnectorshas36gridpoints,thecenteronesharesoneofitsendpointswitheachofitsneighborsreducingthetotalfortheedgeby2).OnceEnterhasbeenpicked,Done-ApplyNewDimsisclickedtofinish.,28,(Re)DistributeConnectors,Itsalsopossibletoalterthedistributionofgridpointsalongconnectors.Thiswillbediscussedinmoredetaillater.,UnderCONNECTORCOMMANDS,pickSetsVals.,Selectsubconnector(s)forwhichthedistributionistobereset.,Then,SelectDone.,Thenewsvaluecanthenbeenteredandapplied.,s=0,s=0.01,Building2DStructuredGrids,Inthepresentexample,thegridpointswillremainevenlydistributed.,29,AssembleDomains,Building2DStructuredGrids,Allisnowreadytoassembletheconnectorsintothefouredgesthatwillboundthedomainofthemesh.,IntheMAINMENU,pickDomainstoswitchtothatmenu.,Next,selecttheCreatecommandtobeginbuildingthenewdomain.,Besurethatstructuredcelltypeischosen,thenpickAssembleEdges.,Adomainschematicwillappear,aswillseveralchoices.EnsurethatAutoNextEdgeisoff,andAutoCompleteison.,30,AssembleDomains(Continued),Building2DStructuredGrids,Thefirstedgewillconsistofthethreebottomconnectors.Themouseisusedtoselecttheseinturnfromlefttorightthepicturehereshowsthesceneafterthefirsttwohavebeenpickedwiththemousecursorpoisedtoselectthethird.Oncethisconnectorhasbeenadded,NextEdgeisselectedtotellGridgentheedgeiscomplete.Themouseisthenusedtoselecttheconnectorontherightsideofthedomaintobe.WhenNextEdgeisagainselectedafterthat,thedomainwillautocompleteitself.,31,AssembleDomains(Continued),Building2DStructuredGrids,Thisisthedomainthatresults.Notethatthemeshinthevicinityoftheleadingedgeoftheairfoilisabitroughlooking.ThiscanbecorrectedwithalittlesmoothingdonewithGridgensstructuredsolver.TogetbacktotheDOMAINCOMMANDSmenutodothis,selectDone.,32,TheStructuredSolver,Building2DStructuredGrids,Torunthesolver,firstchooseRunSolverStructuredfromtheDOMAINCOMMANDSmenu.,Thedomainisnextpickedinthiscasebyhighlightingtheentryinthebrowserwindow.OnceDoneisselected,theparametersfortheellipticsolvercanbeselected.,Inthisinstance,theRunNIterationsbuttonisselected,and10isenteredviathekeyboard.ClickingEnterwillthenstartthesolver.,33,TheStructuredSolver(Continued),Building2DStructuredGrids,Themeshlineswillshiftasthesolverruns,endingwiththesmoothedmeshasshownhere.DoneSaveisselectedtosavethechanges.,34,AssembleBlocks,Building2DStructuredGrids,FromtheMAINMENU,Blocksisselected.,Thegridblockisnextassembledfromthedomain,inmuchthesamewayasadomainisassembledfromitsconnectoredges.,CreateisthenselectedfromtheBLOCKCOMMANDSmenu.,ThisopenstheCREATEBLOCKsubmenu.EnsurethestructuredcelltypeistoggledbeforeclickingonAssembleFaces.,ThenextstepistopickAdd1stFacetobeginformingtheblock.,35,AssembleBlocks(Continued),Building2DStructuredGrids,Thefaceisselectedbymouseclickingonitsimageinthedisplaywindow.Sincethisisa2Dblock,oncetheSavetheFacebuttonispressed,theblockiscomplete.,PressDoneSaveBlockstofinishthisstep.,36,SetAnalysisBoundaries,Building2DStructuredGrids,ThefinalstepingeneratingthemeshissettinguptheboundariesfortheCFDsoftware.,FromtheMAINMENU,theAnalysisS/Wsubmenuisselected.,SetBCsisthenpicked.,37,SetAnalysisBoundaries(Continued),Building2DStructuredGrids,Theindividualconnectorsthatwillmakeupeachboundarycanthenbehighlightedbymouseinthedisplaywindow.Onceallofthedesiredconnectorsthatwillmakeaboundaryareselected,Doneispickedtobringupasecondmenutospecifytheboundarytypetobeassignedtothatcollection.Inthiscase,theinlettotheflowfieldisbeingselected.Theotherboundariesarespecifiedinthesamemanner.,38,ExportandSaveFiles,Building2DStructuredGrids,ThemeshandboundaryconditionsarenowreadytobeexportedforusewiththeCFDsoftware.,FromtheMAINMENU,Input/Outputisselected.,Fromhere,theindividualfilescanbeexported.,Thewindowforwritingthefilesisbasicallyidenticaltothatusedtoinputthedatabasefilesatthebeginningofthegridgenerationprocess.,39,Building2DUnstructuredGrids,Building2DUnstructuredGrids,Itsnowtimetobuildtheunstructuredblockaroundthelowerhalfoftheairfoil.,Thefirstfewsteps(selectingtheanalysissoftware,settingdefaultsinthiscasetheconnectordimension,andimportingthedatabasegeometry)arethesameasbefore.Tosavesometime,itwillbeassumedthatthesehavealreadybeenperformed.,40,The“Bottom-Up”GridgenProcess,SelectAnalysisSoftwareandMeshDimensionalityImportandManipulateDatabaseGeometryCreateSegmentsandConnectorsDimensionConnectorsandDistributeGridPointsAssembleDomainsAssembleBlocksSetupCFDAnalysisBoundariesExportandSaveFiles,Building2DUnstructuredGrids,41,CreateConnectors,Everythingisthussettostartbuildingtheconnectorsthatwillmakeupthegridsedges.,IntheMAINMENU,Connectorsischosentobringupthecorrespondingcommandsmenu.,SelectCreatetoopentheCreateConnectorsubmenu,Asthefirstconnectorwillbelaiddownontheairfoildatabasegeometry,pickOnDBEntities.,Building2DUnstructuredGrids,42,CreateConnectors(Continued),Asseenpreviously,theairfoiliscomposedoftwodatabaseentities,onefortheuppersurfaceandoneforthelower.Themousecanbeusedtopickthecurveforthelowersurfacefromthelistintheblackboardwindowordirectlyfromthedisplaywindow.Notethatplacingthemousecursorovereithertheentryinthetableortheentityinthedisplayhighlightsbothtoaidtheselectionprocess.,ClickingonDonecompletestheprocess.,Building2DUnstructuredGrids,43,CreateConnectors(Continued),Asbefore,the2PointConnectorsoptionisusedtocreatetheremainingconnectors.SinceGridgeninitiallypositionsthedisplaycursoratthelastendpointofthepreviouslydefinedconnector,itspossibletoquicklyboxintheairfoilfrombelow.Here,thecursorispositionedbackattheleadingedgeoftheairfoil,readytopickthefinalendpointofthelastconnectorneededtocompletethecircuit.,Withthecursorinposition,thelastconnectorcanbecompletedbyPicking.,Building2DUnstructuredGrids,2,-1,0,-1,-1,0,2,0,0,-1,0,0,44,CreateConnectors(Continued),Withthelastconnectorcompleted,clickonDoneCreatingConnsintheCREATECONNECTORmenu(orjusthitthehotkey,esc).Unlikeastructureddomain,theunstructuredonebeingbuiltinsidetheseconnectorswillnotrequirebalancednumbersofgridpointsonoppositeedges(indeedtherewillbeonlyoneedgethatsurroundstheentiredomain).However,topromoteauniformcelldensity,itwillstillbedesirabletoredimensionthatlongconnectoratthebottomtohaveroughlyasmanygridpointsasthethreeconnectorsontheothersidehavecombined.Sincethestepstodothisarethesameaspreviouslyshown,justthefinalresultisdisplayedhere.,Building2DUnstructuredGrids,45,AssembleDomains,Everythingisnowreadytoassembletheconnectorsthatwillboundthemeshdomain.,IntheMAINMENU,pickDomainstoswitchtothatmenu.,Next,selecttheCreatecommandtobeginbuildingthenewdomain.,Besurethatunstructuredcelltypeischosen,thenpickAssembleEdges.,Asanunstructureddomaincanhaveanynumbe