FLUENT - Tutorial - Dynamic mesh - Solving a 2D Vi

Tutorial:Solvinga2DVibromixerProblemUsingtheDynamicMeshModelIntroductionThedynamicmeshmodelinFLUENTcanbeusedtomodelflowswheretheshapeofthedomainischangingwithtimeduetomotiononthedomainboundaries.Themotioncanbeeitheraprescribedmotion(e.g.,youcanspecifythelinearandangularvelocitiesaboutthecenterofgravityofasolidbodywithtime)oranunprescribedmotionwherethesubsequentmotionisdeterminedthroughauser-definedfunction(UDF).TheupdateofthevolumemeshishandledautomaticallybyFLUENTateachtimestepbasedonthenewpositionsoftheboundaries.Tousethedynamicmeshmodel,youneedtoprovideastartingvolumemeshandthedescriptionofthemotionofanymovingzonesinthemodel.ThistutorialdemonstratestheuseofFLUENT’sdynamicmeshcapabilitiesforavibromixer,adevicewithaperforated(cylindrical)plateofsmallthicknessthatmoveswithasinusoidalmotionwhichisimplementedthroughaUDF.Inthistutorialyouwilllearnhowto:•Setupaproblemforadynamicmesh•Specifydynamicmeshmodelingparameters•Specifythemotionofdynamiczones•Previewthedynamicmeshbeforestartingthecalculation•Performbasicdynamicmeshcalculationswithresidualplotting•ExaminethepressureandvelocityfieldsusinggraphicsPrerequisitesThistutorialassumesthatyouarefamiliarwiththeFLUENTinterfaceandhavecompletedTutorial1fromtheFLUENT6.2TutorialGuide.Someofthebasicstepsinthesetupandsolutionprocedureswillnotbeshownexplicitly.Youshouldbefamiliarwiththedynamicmeshmodel.Ifyouarenot,youcanreferSection10.6:DynamicMeshesintheFLUENT6.2User’sGuide.cFluentInc.April1,20051Solvinga2DVibromixerProblemUsingtheDynamicMeshModelPreparation1.Copythefiles,vibromix2d.msh,vibromixbin.scm,vibromix.binandvibromix-2d.ctoyourworkingdirectory.2.Startthe2DversionofFLUENT.SetupandSolutionStep1:Grid1.Readthegridfile,vibromix2d.msh.File−→Read−→Case...Asthemeshfileisreadin,messageswillappearintheconsolewindowreportingtheprogressofthereading.2.Checkthegrid.Grid−→CheckFLUENTwillperformvariouschecksonthemeshandwillreporttheprogressintheconsolewindow.Payattentiontothereportedminimumvolumeandmakesurethisisapositivenumber.3.Displaythegrid(Figure1).Display−→Grid...2cFluentInc.April1,2005Solvinga2DVibromixerProblemUsingtheDynamicMeshModel(a)UnderSurfaces,keepthedefaultselectionofthesurfaces.(b)ClickDisplayandclosethepanel.Figure1displaysthethreefluidzones:bottom-zone,movingzone(midzone)andtopzone.Figure1:Gridforthe2DVibromixerGeometrycFluentInc.April1,20053Solvinga2DVibromixerProblemUsingtheDynamicMeshModelStep2:Models1.Enableatime-dependentcalculation.Define−→Models−→Solver...(a)SelectUnsteadyunderTime.(b)KeepthedefaultUnsteadyFormulationof1st-OrderImplicit.Dynamicmeshsimulationscurrentlyworkonlywithfirst-ordertimeadvance-ment.4cFluentInc.April1,2005Solvinga2DVibromixerProblemUsingtheDynamicMeshModel2.Turnonthestandardk-viscousmodelwithstandardwallfunctions.Define−→Models−→Viscous...3.Readtheschemefileforspecifyingmotionparameters(vibromixbin.scm).File−→Read−→Scheme...Theschemefile,vibromixbin.scm,loadsthevibromix.binfile,whichcreatestheDefine/User-Defined/MotionParameters...menuitem.Thispanelthatisopenedusingthismenuitemisusedtospecifythefrequencyandamplitudevaluesofthemotion.4.Setthefrequencyandamplitudemotionparameters.Define−→User-Defined−→MotionParameters...(a)SettheFrequencyto10Hz.(b)SettheAmplitudeto0.1m.cFluentInc.April1,20055Solvinga2DVibromixerProblemUsingtheDynamicMeshModelStep3:Materials1.Copyliquidwaterfromthematerialsdatabase.Define−→Materials...(a)ClicktheFluentDatabase...buttonintheMaterialspanel.TheFluentDatabaseMaterialspanelwillopen.(b)InthelistofFluentFluidMaterials,selectwater-liquid(h2ol).(c)ClickCopytocopytheinformationforliquidwatertoyourmodel.(d)ClosetheFluentDatabaseMaterialspanelandtheMaterialspanel.6cFluentInc.April1,2005Solvinga2DVibromixerProblemUsingtheDynamicMeshModelStep4:BoundaryConditionsDefine−→BoundaryConditions...Inthisstep,youwillchangethefluidtypetowaterforeachoneofthethreefluidzones-bottom-zone,movingzone,andtopzone1.Settheconditionsforthefluid,bottom-zone.(a)Selectwater-liquidintheMaterialNamedrop-downlist.cFluentInc.April1,20057Solvinga2DVibromixerProblemUsingtheDynamicMeshModel2.Settheconditionsforthefluid,movingzone.(a)Selectwater-liquidintheMaterialNamedrop-downlist.3.Settheconditionsforthefluid,topzone.(a)Selectwater-liquidintheMaterialNamedrop-downlist.Step5:User-DefinedFunction1.CompiletheUDF,vibromix-2d.c,usingtheCompiledUDFspanel.Define−→User-Defined−→Functions−→Compiled...(a)MakesurethattheUDFsourcefile,vibromix-2d.c,isinthesamedirectorythatcontainsyourcaseanddatafiles.(b)SelecttheUDFsourcefilebyclickingAdd...underSourceFilesintheCompiledUDFspanel.ThiswillopentheSelectFilepanel.(c)IntheSelectFilepanel,selectvibromix-2d.c.(d)IntheCompiledUDFspanel,enterthenameofyourlibrarydirectory(e.g.,libudf2d)andclickBuildtobuildasharedlibraryforyoursourcefile.(e)ClickLoadtolinkyoursharedlibrarytotheFLUENTexecutable.8cFluentInc.April1,2005Solvinga2DVibromixerProblemUsingtheDynamicMeshModelStep6:MeshMotionSetup1.Activatedynamicmeshmotionandspecifytheassociatedparameters.Define−→DynamicMesh−→Parameters...(a)UnderModels,selectDynamicMesh.Thepanelwillexpandtoshowadditi