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1、PHYSICSOFFLUIDSVOLUME16,NUMBER11NOVEMBER2004Energytransfersandspectraleddyviscosityinlarge-eddysimulationsofhomogeneousisotropicturbulence:ComparisonofdynamicSmagorinskyandmultiscalemodelsoverarangeofdiscretizationsa)ThomasJ.R.HughesTheUniversityofTexasatAustin,201E
2、ast24thStreet,ACES6.412,1UniversityStationC0200,Austin,Texas78735-0027GarthN.WellsFacultyofCivilEngineeringandGeosciences,DelftUniversityofTechnology,Stevinweg1,2628CNDelft,TheNetherlandsAlanA.WrayNASAAmesResearchCenter,MoffettField,California94035(Received29July200
3、3;accepted13July2004;publishedonline5October2004)Energytransferswithinlarge-eddysimulation(LES)anddirectnumericalsimulation(DNS)gridsarestudied.ThespectraleddyviscosityforconventionaldynamicSmagorinskyandvariationalmultiscaleLESmethodsarecomparedwithDNSresults.Bothm
4、odelsunderestimatetheDNSresultsforaverycoarseLES,butthedynamicSmagorinskymodelissigni®cantlybetter.Formoderatelytowell-re®nedLES,thedynamicSmagorinskymodeloverestimatesthespectraleddyviscosityatlowwavenumbers.ThemultiscalemodelisingoodagreementwithDNSforthesecases.T
5、heconvergenceofthemultiscalemodeltotheDNSwithgridre®nementismorerapidthanforthedynamicSmagorinskymodel.©2004AmericanInstituteofPhysics.[DOI:10.1063/1.1789157]I.INTRODUCTIONbasebyintroducinganarbitrarycutoffbelowtheDNSlimit3,4ofresolution.Theeddyviscosityiscalculated
6、byexamin-Thetransferofenergybetweendifferentscalesofmo-ingtheenergytransferfromamodebelowthecutofftotioninaturbulent¯owhasbeenstudiedwidelyforhomoge-resolvedmodesbeyondthecutoff.Thesecalculationsgiveanneousisotropicturbulence.The¯owofenergybetweendif-indicationofthe
7、eddyviscositythatwouldberequiredforanferentwavenumbermodesisoftenexpressedusingtheeffectivelargeeddysimulation(LES)inwhichthecutoff1conceptofaneddyviscosity.HeisenbergexaminedthelosscorrespondstotheLESlimitofresolution.DNSresultscon-ofenergy,intheFourierdomain,fromm
8、odeswithinthe®rmedthepresenceofacuspclosetothecutoffwavenum-intervalk=f0,kcgtomodesoutsidetheinterval.Thetransferber.However,noplateauatlo
