ERCOFTAC_Best_Practice_Guidelines_for_Industrial_C

ERCOFTACBestPracticeGuidelinesforIndustrialCFDM.CaseyandT.WintergersteFluidDynamicsLaboratorySulzerInnotecA.G.HuttonQinetiQLtd.Quality&trust-akeyissuePotentialofCFDinindustryisenormousTake-upacrossallsectorsissteadilyincreasing.SeveralsophisticatedcommercialpackagesavailableExperiencerevealsitisdifficulttoapplyCFDsuccessfullyintheindustrialcontextEveninthehandsofcompetentfluiddynamicists,thequalityandfidelityofresultsremainuncertain.Reliabilityisthemostpressingissuehinderingthedeliveryoffullpotential.Theneedforbestpracticeguidelines!ERCOFTAC/IAHRWorkshopTURBINE99VattenfallUtvecklingABCreatedbyJohnBergstrom,LuleåUniversityofTechnologyCADmodelThepressurerecoveryfactor(efficiency)ofthedrafttubeWhat‘stheproblem?CFDisalwaysapproximatewithmanyerrorsourcesModelerrorsanduncertainties•Differencebetweenexactsolutionoftheequationsandrealflow•TurbulencemodeluncertaintiespredominateDiscretisationornumericalerror•Differencebetweenexactsolutionandsolutiononafinitegrid•InindustrialCFDsolutionsareusuallynotgridindependentIterationorconvergenceerror•DifferencebetweenconvergedsolutionandresultafternstepsRound-offerrorsApplicationuncertainties•UncertainboundaryconditionsorgeometryUsererrors•Mistakes,blunders,carelessness,optimism,etc.,Programmingorcodeerrors(bugs)ThewayforwardERCOFTACinitiativeon‘Quality&TrustinIndustrialCFD’plannedtoproceedintwophasesPhase-1.BestPracticeGuidelinesGenericAdviceonhowtocarryoutqualityCFDcalculationsCommonbestpracticesothatseparateanalysesofthesameproblemusingsamephysicalmodelproduceconsistentresultsPhase-2.ApplicationProceduresGuidanceonhowtointerpretanddeployCFDresultswithtrustCompilationofCFDcalculationsofarangeofindustrialtestcasesPerformanceofvariousclosuremodelsanalysedBoundsquantifiedandadvicegivenonlevelsoftrustinengineeringparametersPhase2isbeingpursuedviatheQNET-CFDThematicNetworkGenesisoftheBestPracticeGuidelinesLaunchmeetingofSIGinParis199741membersofSIG,eachpayingafeeAcrossallsectorsandEUcountries.IncludesmajorcodevendorsBPGdevelopedbySulzerInnotecundercontractinfullconsultationwithprovidersandusersofCFD(academics,specialists&codevendors)Materialfleshedoutatexpertsworkshop,Zurich,June1999FirstDraftrevisedinlightofexperts’commentsFinalVersion(FirstEdition)January2000.RepresentstheconsensusviewofEuropeanCFDCommunityWhohelpedinthepreparationoftheBPG?Co-ordinationandediting:Dr.MichaelCaseyandTorstenWintergerste(SulzerInnotec)Sevenmajorcodevendorsandcodedevelopers:AEA,FLUENT,NUMECA,STAR-CD,EDF,CEA,BritishEnergyManyindividualswithCFDexperiencefromawiderangeofcompanies,universities,andcountriesDr.G.Scheuerer,Dr.F.Menter,Dr.J.Ferreira,DrJ.StokesandDr.S.Phillipson(AEATechnology),Dr.F.Mendonca(ComputationalDynamics),Dr.M.Rabbitt(BritishEnergy),Prof.M.A.Leschziner(UniversityofLondon),Prof.I.Castro(UniversityofSurrey),Dr.C.LeaandDr.A.Kelsey(HSE),Dr.S.Gilham(WSA),Dr.N.Hakimi(Numeca),Dr.P.Wild(Fluent),Dr.E.Benz(ABB),Dr.J.Vos(EPFL),Prof.A.Hutton(DERA),Dr.C.Carey(Alstom),Dr.N.Rhodes(MottMacdonald),Dr.P.Tucker(NAFEMS),Dr.P.Andreasson(VattenfallUtveckling),Prof.Ch.Hirsch(VUB),Prof.W.Rodi(UniversityofKarlsruhe),Dr.F.Klimetzek(DaimlerChryslerCars),Dr.W.Haase(DaimlerChryslerAerospace),Dr.F.ArchambeauandDr.N.Gay(EDF),Dr.H.Paillere(CEA),H.-D.Grein(NEC),DrP.DrtinaandDr.H.Keck(SulzerHydro).Dr.M.Casey,Dr.ELang,Dr.P.Holbein,Dr.M.Wehrli,MissE.WiederkehrandT.Wintergerste(SulzerInnotec)Many,manythankstoallconcerned!Howaretheguidelinesorganised?Objectives:Guidetoavoidthemostcommonpitfalls:•essentialinformationforthenoviceuser,•usefulinformationformanagementandforregulatorybodies,•advicethatcanalsohelptheexperiencedexpertuserGuidelinesnotspecifictoindividualcodes,methodsorapplicationsGuidelinesthathaveverywidesupportNotexhaustive:20%ofrulestocover80%ofaspectsModularformforeachtopic:Discussionsection•Problemdescriptionanddiscussion,includingreferencestoimportantbooks,articlesandreviewswithrelevantexamplesfortheuser.•Guidelinessection:•Shortsimplestatementsofadvicewhichprovideclearguidance,aregenerallyaccepted,andareeasilyunderstandablewithoutelaboratemathematics.What‘sthestructureoftheBPG?(1)Chapter1:IntroductionChapter2:SourcesoferrorsanduncertaintiesDefinitions-validation,verification,calibration,error,uncertaintyChapter3:Numerical,convergence,round-offerrorsChapter4:TurbulenceModellingConcentrationonstandardk-εmodelwithwallfunctionsChapter5:ApplicationuncertaintiesChapter6:UsererrorsChapter7:CodeerrorsChapter8:ValidationandSensitivitytestsWhat‘sthestructureoftheBPG?(2)Chapter9:TestcasesEighttestcasesfromvendorsanddevelopers,eachofwhichexaminestwoorthreeseparateissuesarisingintheguidelines•STAR-CD:2-Dtransientscalarbubbleconvectingat45degrees•EDF:T-junctionbetweenmainandauxiliarypipe•CEA:Naturalconvectionflowinasquarecavity•BritishEnergy:Suddenpipeexpansion•STAR-CD:TransonicairfoilRAE2822•FLUENT:Enginevalve•NUMECA:Lowspeedcentrifugalcompressor•AEA:TurbulentflowinamodeloutletplenumChapter10:NeedforfurtherworkChapter11:ChecklistofBestPracticeGuidelinesChapt