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ID:39960646
大小:901.50 KB
页数:18页
时间:2019-07-16
《ansys12.0cfx官方教程15a》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、Chapter15ReviewandTipsIntroductiontoCFXDomainInterfacesDomainInterfacescanbeusedaspartofameshingstrategyaswellasforconnectingdifferentdomainsorreferenceframestogetherBoundaryconditionsarecreatedineachdomainwhenaDomainInterfaceiscreated;generallyyoushoul
2、dnoteditthesedirectlyWhenthemeshisdifferentoneachsideoftheinterfaceaGGI(GeneralGridInterface)isusedThiswillusemorememoryintheSolverthanacontinuousmeshAccuracyacrossaGGIinterfaceisusuallynotaconcernaslongasthemeshlengthscalesoneachsidearesimilarAutomaticDo
3、mainInterfacesarecreatedbyCFX-PreinsomecasesAlwayschecktheseanddon’tassumethatalltherequiredDomainInterfaceshavebeencreatedSourcesSourcesareusedtoaccountforphysicsorprocessesthathavenotbeendirectlyresolvedinthesimulationMomentumsourcescanbeusedtocreateapr
4、essuredrop(e.g.ascreen,aporousmaterial)orapressurerise(e.g.afan)Energysourcescanaccountforheatadded/removedfromthesimulationWhensourcesarefunctionsofthesolvedvariable(e.g.momentumsourcesthatarefunctionsofvelocity,energysourcesthatarefunctionsoftemperature
5、)theSourceCoefficientshouldbesetTheSourceCoefficientmustbenegativeotherwisethesolverwilldivergeMayneedtore-writetheSourcesothatishasanegativederivativeTransientSimulationsInatransientanalysisthetimestepshouldbesmallenoughtocapturethetransientbehaviourofin
6、terestBoundaryconditionscanbefunctionsoftimeConvergenceshouldbemonitoredsothateachtimestepisconvergedItisgenerallybettertoreducetheoveralltimestepsizetoimproveconvergenceratherthanincreasingthenumberofcoefficientloopsRemembertocreatetheTransientResultsobj
7、ectbeforerunningTurbulenceEstimatetheflowReynoldsNumbertodetermineiftheflowislaminarorturbulentChecky+valuestomakesurethenear-wallmeshissuitabley+<300foraWallFunctionsolutiony+<=2withtheSSTmodelforalow-ResolutionTheSSTmodelisagoodchoiceforageneralturbulen
8、cemodelBeawareofthelimitationsoftheturbulencemodelchosenRANSmodelsresolvethemeanflowfield,thereforealotoftransientturbulentstructuresarenotcapturedThesemaybeimportantwhensimulatingnoiseandvibrationThek-emodelcangive
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