Gridgen经典培训教程

1 Inthissession GridgenTerminology GUIComponents GridgenHelp Building2DStructuredGrids Building2DUnstructuredGrids Tutorial 2DBump BasicSkills GridgenTraining Overview 2 What sanEntity 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 Analytic curveandsurfaceinformationfromaCADfile Shell discreteunstructureddatabasesurfaceentity generallyimportedfromstereolithography STL formattedfiles Network bilinear 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 ZoomPressandholdthecentermousebuttontochangethemodelimage ssize pushingthemouseawayfromyouzoomsoutwhilepullingittowardsyouzoomsin Formicewithacenterwheel thewheelcanberolledorhelddowntocontrolzoom Ontwobuttonmice zoomingisaccomplishedbyholdingbothbuttonsdown Whilezooming themousecursorchangesto RightMouseButton PickPressandreleasetherightmousebuttontoselectcommandsfromthecommandmenuorpickentitiesinthedisplaywindoworbrowserlist Whilepicking themousecursorchangesto GUIComponents 10 SomeMouseOptions GUIComponents Thefunctionsoftheleftandrightmousebuttonscanbereversed sothatleftisforpickingandrightisforpanning ThiscanbedonebyselectingLeftPk Whendealingwithsmallergeometricentities itmayalsobedesirabletoreducethemousesensitivityinpanning zooming androtatingthescreenimage Thiscanbedonebyclickingonthe button moreclicks lesssensitivity Youmaywishtochangesomeofthedefaultmousesettings ThesecanbeaccessedbyselectingtheDisplayorDispsubmenufromGridgen sMAINMENU 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 and numpadkeysreversethedirectionofakeyboardmodelrotation Altusedwithanumpadmodelrotationgivesasingleincrement 3deg rotation GUIComponents 13 CommonlyUsedHotKeys GUIComponents Note HotkeysforGridgencommandsareshownaspinkcharactersonthecorrespondingGUIbuttons 14 FileBrowsing SelectingInput OutputfromtheMAINMENUopenstheINPUT OUTPUTCOMMANDSsubmenufromwhich inthisexample theINPUTGridgenFILEsubmenuhasbeenselected TheBrowserWindowshowstheappropriatecontentsofthecurrentworkingdirectory Themousecanbeusedtoscrollthroughandselectfromlist SelectingTypein Nameallowsyoutotypeinafilenameforimportorexport whileTypein Dirletsanewworkingdirectorytobeset SelectingGotoDir inUnix willprovidelistofavailabledrivestochangetoascurrentworkingdirectory whileGotoDir OrigchangestheworkingdirectorybacktotheoriginaldirectorywhereGridgenwasopened GUIComponents Oncefilehasbeenselected Openisclicked 15 FileBrowsing Continued UponenteringtheTypein Namemode thetextinputwindowwillechothefilenameenteredviathekeyboard Oncethenameisentered theEnterkeyonthekeyboardorOpenbuttonintheGUImustbeclicked Theesckeycanbeusedtoexitfromtextinput Noothercommandsormanipulationsareavailablewhileinthismode Glyphexpressionsarevalid GUIComponents 16 GridgenFileNames GridgenRestartFiles gg containentiregridmodelsfromcontrolpointdefinitionsthroughboundaryconditionsettings Theyonlyreferencedatabaseinformation CompositeDatabaseFiles dba store inGridgen snativedatabasemodelformat datafromalldatabasesources aswellasdatabaseentitydisplayattributesandlayerinformation GUIComponents 17 GridgenHelp GridgenHelp Gridgen shtml 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 It snowpossibletostartbuildingtheconnectorsthatwillmakeuptheedgesofthegrid 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 andthedisplaycursorispositionedatthatconnector strailingendpoint Thetrailingendpointforthislastconnectorisalsotheleadingedgeendpointfortheconnectorappliedtotheairfoil suppersurface 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 orhitthehotkeycombination ac Asshown it sclearthattherearefarmoregridpointsalongthebottomedgethanthetop sincetherearethreeconnectorsbelowtotheoneabove buteachwiththesamedefaultdimension Thishastobecorrectedbeforethedomaincanbebuilt Building2DStructuredGrids 27 Re DimensionConnectors Building2DStructuredGrids IntheCONNECTORCOMMANDSmenu selectRedimensionGrids Thiswillallowthetopconnectortobepickedinthedis playwindowviathemouse anditsnewdimensiontobeenteredviathekey board Inthiscase 106isthatnewdimension whileeachofthethreebottomconnectorshas36gridpoints thecenteronesharesoneofitsendpointswitheachofitsneighborsreducingthetotalfortheedgeby2 OnceEnterhasbeenpicked Done ApplyNewDimsisclickedtofinish 28 Re DistributeConnectors It salsopossibletoalterthedistributionofgridpointsalongconnectors Thiswillbediscussedinmoredetaillater UnderCONNECTORCOMMANDS pickSet sVals Selectsubconnector s forwhichthedistributionistobereset Then SelectDone Thenew svaluecanthenbeenteredandapplied 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 Themouseisusedtoselecttheseinturnfromlefttoright thepicturehereshowsthesceneafterthefirsttwohavebeenpickedwiththemousecursorpoisedtoselectthethird Oncethisconnectorhasbeenadded NextEdgeisselectedtotellGridgentheedgeiscomplete Themouseisthenusedtoselecttheconnectorontherightsideofthedomaintobe WhenNextEdgeisagainselectedafterthat thedomainwillautocompleteitself 31 AssembleDomains Continued Building2DStructuredGrids Thisisthedomainthatresults Notethatthemeshinthevicinityoftheleadingedgeoftheairfoilisabitroughlooking ThiscanbecorrectedwithalittlesmoothingdonewithGridgen sstructuredsolver TogetbacktotheDOMAINCOMMANDSmenutodothis selectDone 32 TheStructuredSolver Building2DStructuredGrids Torunthesolver firstchooseRunSolverStructuredfromtheDOMAINCOMMANDSmenu Thedomainisnextpicked inthiscasebyhighlightingtheentryinthebrowserwindow OnceDoneisselected theparametersfortheellipticsolvercanbeselected Inthisinstance theRunNIterationsbuttonisselected and10isenteredviathekeyboard ClickingEnterwillthenstartthesolver 33 TheStructuredSolver Continued Building2DStructuredGrids Themeshlineswillshiftasthesolverruns endingwiththesmoothedmeshasshownhere Done Saveisselectedtosavethechanges 34 AssembleBlocks Building2DStructuredGrids FromtheMAINMENU Blocksisselected Thegridblockisnextassembledfromthedomain inmuchthesamewayasadomainisassembledfromitsconnectoredges CreateisthenselectedfromtheBLOCKCOMMANDSmenu ThisopenstheCREATEBLOCKsubmenu EnsurethestructuredcelltypeistoggledbeforeclickingonAssembleFaces ThenextstepistopickAdd1stFacetobeginformingtheblock 35 AssembleBlocks Continued Building2DStructuredGrids Thefaceisselectedbymouseclickingonitsimageinthedisplaywindow Sincethisisa2Dblock oncetheSavetheFacebuttonispressed theblockiscomplete PressDone SaveBlockstofinishthisstep 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 It snowtimetobuildtheunstructuredblockaroundthelowerhalfoftheairfoil Thefirstfewsteps selectingtheanalysissoftware settingdefaults inthiscasetheconnectordimension andimportingthedatabasegeometry arethesameasbefore Tosavesometime itwillbeassumedthatthesehavealreadybeenperformed 40 The Bottom Up GridgenProcess SelectAnalysisSoftwareandMeshDimensionalityImportandManipulateDatabaseGeometryCreateSegmentsandConnectorsDimensionConnectorsandDistributeGridPointsAssembleDomainsAssembleBlocksSetupCFDAnalysisBoundariesExportandSaveFiles Building2DUnstructuredGrids 41 CreateConnectors Everythingisthussettostartbuildingtheconnectorsthatwillmakeupthegrid sedges IntheMAINMENU Connectorsischosentobringupthecorrespondingcommandsmenu SelectCreatetoopentheCreateConnectorsubmenu Asthefirstconnectorwillbelaiddownontheairfoildatabasegeometry pickOnDBEntities Building2DUnstructuredGrids 42 CreateConnectors Continued Asseenpreviously theairfoiliscomposedoftwodatabaseentities onefortheuppersurfaceandoneforthelower Themousecanbeusedtopickthecurveforthelowersurfacefromthelistintheblackboardwindowordirectlyfromthedisplaywindow Notethatplacingthemousecursorovereithertheentryinthetableortheentityinthedisplayhighlightsbothtoaidtheselectionprocess ClickingonDonecompletestheprocess Building2DUnstructuredGrids 43 CreateConnectors Continued Asbefore the2PointConnectorsoptionisusedtocreatetheremainingconnectors SinceGridgeninitiallypositionsthedisplaycursoratthelastendpointofthepreviouslydefinedconnector it spossibletoquicklyboxintheairfoilfrombelow 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 Asanunstructureddomaincanhaveanynumberofedges theblackboardwindownowjustshowswhichedgeiscurrentlybeingformed MakesureAutoCompleteandAutoSaveareturnedon Aseachconnectorisadded thelatterwillcheckwhethertheloophasbeenclosedandwillautomaticallysaveandinitializethedomainwhenitis Building2DUnstructuredGrids 46 AssembleDomains Continued Thenextstepistoselec