FLUENT - Tutorial - Dynamic mesh - Projectile Movi

Tutorial:ProjectileMovingInsideaBarrelIntroductionThepurposeofthistutorialistoillustratehowtosetupandsolveaproblemusingthefollowingtwofeaturesinFLUENT.•MovingDeformingMesh(MDM)usingthelayeringalgorithm.•User-definedrealgaslaw.Theprobleminvolvesaprojectilemovingthroughabarrelandoutofthemuzzle.Theflowisassumedtobeinviscid.Inthistutorialyouwilllearnhowto:•ReadameshfileforperforminganMDMcalculation.•CompileaUDFfortheprojectilemotionandtheAbel-Nobelrealgaslaw.•SetupthemovingzonesandhooktheUDFinFLUENT.•Runanunsteadycalculationfortheproblemusingcoupledsolverandaxisymmetry.•Createanimations.PrerequisitesThistutorialassumesthatyouarefamiliarwiththeFLUENTinterfaceandhavecompletedTutorial1fromtheFLUENT6.1TutorialGuide.Someofthebasicstepsinthesetupandsolutionprocedureswillnotbeshownexplicitly.Youshouldbefamiliarwiththedynamicmeshmodel.Ifyouarenot,pleasereviewSection9.6:DynamicMeshesintheFLUENTUser’sGuide.Note:Assumingthatyouareusingasingleprocessormachinewithaclockspeedof2GHz,thistutorialwilltake:•Onehourtoworkthroughit.•Anadditional6hoursforthecalculationsuptotheuncorkingoftheprojectile.•Anadditional43.5hoursforthecalculationsuntiltheprojectileleavesthefieldofview.cFluentInc.March27,20061ProjectileMovingInsideaBarrelProblemDescriptionAprojectileweighing120gramsisinitiallyatrestinsidea20mmcaliberbarrel.Thegasinsidethechamberispatchedatahighpressureof3000atmandatemperatureof2700K,andtheprojectileisreleased.ThemotionoftheprojectileiscomputedusingaUDFbasedonFLUENT’sSixDegreeofFreedomUDF.Inthiscase,onlythepressureforcesareconsidered,whiledragandme-chanicalfrictionareneglected.Theprojectileisreleasedatt=0.TheAbel-Nobelequationofstateisimplementedusingtheuser-definedrealgasmodel.Figure1:ProblemSchematicPreparation1.Copythemeshfile,projectile.msh.gzandtheUDFsourcefiles,aneos.candsixdofproperty.c,toyourworkingdirectory.2.Startthe2DversionofFLUENT.2cFluentInc.March27,2006ProjectileMovingInsideaBarrelSetupandSolutionStep1:Grid1.Readthegridfile,projectile.msh.gz.File−→Read−→Case...FLUENTwillreadthefileandreporttheprogressintheconsolewindow.2.Checkthegrid.Grid−→Check3.Reorderthedomain.Grid−→Reorder−→DomainNote:Performthisoperationuntilthebandwidthreductionisintheorderof1.0.4.Scalethegrid.Grid−→Scale...Thismeshwascreatedfora155mmbarrel.Tousethismeshfora20mmbarrelinthistutorial,youneedtoscaleitaccordingly.(a)SettheScaleFactorsforbothXandYto0.129.(b)ClickScaleandclosethepanel.cFluentInc.March27,20063ProjectileMovingInsideaBarrel5.Displaythegrid.Display−→Grid...(a)Retainthedefaultparameters.(b)ClickDisplayandclosethepanel.Figure2:GridDisplay4cFluentInc.March27,2006ProjectileMovingInsideaBarrelFigure3:DimensionsandZoneNamesThisgridwascreatedusingGAMBIT.Theregioninsidethebarrel(onbothsidesoftheprojectile)andtheregionformingtheextensionofthemuzzlearemeshedwithquadsandlumpedintoonefluidzonecalledfluid-mdm.Therestofthedomainconsistsofonefacethatisdisconnectedfromtheotherfaces,andthecorrespondingzoneiscalledfluid-static-outer.Thus,therearetwosetsofedgeswherethetwofluidregionsmeet.Eachsetisturnedintoaninterfacezoneandallowsyoutodefineanon-conformalinterfaceatalaterstage.Boundarylayersareattachedtotheinterfaceedgeatthebottomoffluid-static-outer.Thisportionofthezoneismeshedusingquads.6.Zoomintothemuzzlearea(Figure4).Figure4:MeshNeartheMuzzlecFluentInc.March27,20065ProjectileMovingInsideaBarrelTheentirezone,default-interiorslidestotheright,whilekeepingdefault-interior:001stationary.Atthesametime,cellsarecreatedontheleft(attheedgelabeledbreechinFigure5),anddestroyedontheright(attheedgelabeledp-out-destructinFigure3).7.Zoominnearthebreechandprojectile(Figure5).Figure5showsthedefault-interiorzone,whichwillmovetotheright.Byspecify-ingtherigidbodymotionofdefault-interioryouarealsospecifyingtherigidbodymotionofthewallsbelongingtotheprojectile(w-proj-baseandw-proj-front).Newquadcellsarecreatedattheleftwalllabeledbreech.Conversely,quadcellsaredestroyedattheedgelabeledp-out-destruct.Thecombinationofmovingonezoneasarigidbodywhilecreatinganddestroyingcellsiscalled“layering”.6cFluentInc.March27,2006ProjectileMovingInsideaBarrelFigure5:MeshNeartheBreechandChamber8.Viewthezones,interface-innerandinterface-outer(Figure6).(a)ZoomoutandunderSurfaces,deselectdefault-interior,default-interior:001,andinterface-outertoseewhereinterface-innerislocated.(b)Deselectinterface-innerandselectinterface-outer.Figure6:DefinitionoftheNon-ConformalInterfaceInFigure6,thethreered,dottedlinesegmentsrepresenttheinterface-outerzoneandthesevenbluelinesegments(includingthebottomsofthemuzzlebrakes)representtheinterface-innerzone.cFluentInc.March27,20067ProjectileMovingInsideaBarrelStep2:Models1.Selectthesolver.Define−→Models−→Solver...(a)UnderSolver,selectCoupledandretainImplicitformulation.TherealgaslawworksonlywiththeCoupledsolver.(b)SelectAxisymmetricspaceandUnsteadyand1st-OrderImplicittimeformulation.MDMfeaturescurrentlyworkonlywithUnsteadyand1st-OrderImplicitformu-lation.2.EnabletheEnergyEquation.Define−→Models−→Energy...8cFluentInc.March27,2006ProjectileMovingInsideaBarrel3.Settheviscousmodelt