简介：TheseparatedturbulentflowaroundacircularcylinderisinvestigatedusingLarge-EddySimulation(LES),Detached-EddySimulation(DES,orhybridRANS/LESmethods),andUnsteadyReynolds-AveragedNavier-Stokes(URANS).Thepurposeofthisstudyistoexaminesometypicalsimulationapproachesforthepredictionofcomplexseparatedturbulentflowandtoclarifythecapabilityofapplyingtheseapproachestoatypicalcaseoftheseparatedturbulentflowaroundacircularcylinder.Severalturbulencemodels,i.e.dynamicSub-gridScale(SGS)modelinLES,theDES-basedSpalart-Allmaras(S-A)andk?ωShear-Stress-Transport(SST)modelsinDES,andtheS-AandSSTmodelsinURANS,areusedinthecalculations.Sometypicalresults,e.g.,themeanpressureanddragcoefficients,velocityprofiles,Strouhalnumber,andReynoldsstresses,areobtainedandcomparedwithpreviouscomputationalandexperimentaldata.Basedonourextensivecalculations,weassessthecapabilityandperformanceofthesesimulationapproachescoupledwiththerelevantturbulencemodelstopredicttheseparatedturbulentflow.

简介：海水热力学的二个重要非线性的性质连接了到水密度，cabbeling和弹性(压缩的可能性)的变化，被讨论。埃迪散开和移流在密度导致变化；作为结果，系统的重力的势能被改变。因此，cabbeling和弹性玩在侧面的旋涡散开和移流的energetics给角色调音。垂直旋涡散开是处于全球海洋的机械精力平衡的关键元素之一。垂直旋涡散开能概念上被分开成二步：激动人心并且subscale散开。垂直旋涡向上、温暖/轻的激动人心的推冷/稠密水向下流水；因此，重力的势能被增加。在第二步期间，来自不同地方的水群众通过subscale混合散开，和水密度由于cabbeling被增加。使用WOA01气候学并且假定垂直旋涡扩散性等于2慭楲敮瀠慨潥桰瑹獥?有洠牡湩?桲摯灯票整?ㄠ?挠汨牯灯票整?的经常的价值?挠祲瑰灯票整??栠灡潴桰瑹獥?湡?‵汧畡潣桰瑹獥眠牥?敳畱湥散?眠?獵摥愠朠湥?湡污獹獩洠瑥潨?潴愠慮祬敺琠敨倠?朠湥?敳畱湥散?湩愠杬敡愠摮挠湯楦浲琠敨攠楸瑳湥散漠?桴???敧敮椠?桴?牴湡'諛L瑰浯捩猠煥敵据湩?慤慴漠?桒摯灯票慴愠摮传档潲桰瑹吗？

简介：Anon-linearturbulenthydrodynamicmodelwasproposedbyZhanandLi(1993)usingthelargeeddysimulationapproachanddirectionaleddyviscositymethod.Themodelissimplifiedinthispaperandisappliedtotheproblemofasidedischargeintoopen-channelflow,whereareeireulationzonedevelopsdownstreamofthedischarge.Thenumericalresultsarecomparedwithexperimentalresults(StrazisarandPrahl(1973)andMikhail,Chu,andSavage(1975))andpreviousnumericalresultsobtainedusingak-εmodel(McGuirkandRodi,1978).Theagreementisgood.

简介：AsynopticsnapshotinthisstudyismadefortheEastCapeEddy(ECE)basedontheWorldOceanCirculationExperiment(WOCE)P14CHydrographicSectionandShipboardADCPvelocityvectordatacollectedinSeptember1992.TheECEisananticycloniceddy,barotropicallystructuredandcenteredat33.64°Sand176.21°E,withwarmandsalinouscoredsubsurfacewater.TheradiusoftheeddyisoftheorderO(110km)andthemaximumcircumferentialvelocityisO(40cms-1);asaresult,therelativevorticityisestimatedtobeO(7×10-6s-1).DuetotheexistenceoftheECE,themixedlayernorthofNewZealandbecomesdeeper,reachingadepthof300mintheaustralwinter.TheECEplaysanimportantroleintheformationanddistributionoftheSubtropicalModeWater(STMW)overaconsiderableareaintheSouthPacific.

简介：垂直地在免费表面上侵犯的一口2D槽喷气的流动特征被大埃迪模拟(LES)数字地与一个动态Sub-GridScale(SGS)模型一起调查。σ-坐标转变被介绍印射深度变量物理领域到一件深度制服计算领域。裂口操作员计划，把答案过程切成移流，散开和压力繁殖步，被采用解决即时速度和压力地。一个充分非线性的Lagrange-Euler方法被用来计算免费表面举起。数字结果证明喷气在Eestablished流动(ZEF)的地区保留你方类似，当喷气的骚乱逐渐地变从时对各向同性在表面冲击(ZSI)的地区各向异性。当喷气接近免费表面时，中心线速度很快减少并且流动被免费表面偏斜。二口对称的表面喷气在水平喷气(ZHJ)的地区被形成。超高的AnapproximateGuassian分发也在免费表面上被形成。Thecomputed结果在对可得到的试验性的数据的好同意。

简介：Theconfigurationandaerodynamicperformanceoftheinletsystemareimportantaspectsintheprocessofinstallingagasturbineonanavalvessel.Undertherequirements,largeeddysimulation(LES)isusedtosimulatethethree-dimensionalfluidflowinthewaveblockerofamarineinletfilter.TheSmagorinsky-Lillysub-gridmodelwasusedtomodelmotionsofsmall-scalestructures.Duringnumericalsimulation,theSIMPLEalgorithmwasapplied.Thecentral-differencingspatialdiscretizationschemeandthesecondorderaccuracyfinitedifferenceforthetemporaldiscretizationwereused.Simulationgivessatisfactorydistributionofthevorticityfieldsandturbulentkineticenergy.Comparedwiththek-εturbulentmodel,theresultsofLESarebetterforthedistributionofparameters.Theresultsofexperimentalstudyinasmall-scalewindtunnelindicatethatnumericalcalculationhashigheraccuracy.Therefore,themethodsusedareworthyofreferenceandintroductionforthedesignofaninletsystem.

简介：ResultsofseveralLargeEddySimulations(LES)ofopenchannelflowswithnon-submergedvegetationarepresentedinthisarticle.Itisshownthatthevegetationcanmaketheflowstructureinthemainstreamdirectionuniformforbothsupercriticalandsubcriticalflows.Forsubcriticalflows,theLESresultsoftheensemble-averageoftime-averagedvelocitydistributionsatfourverticalsectionsaroundasingleplantareingoodagreementwithmeasurements.Thevelocityseesdoublepeaksattheupperandlowerpositionsofflows.Forsupercriticalflows,theensemble-averagevelocitiesseesomediscrepancybetweenLESandmeasurementresults.Somesecondaryfloweddiesappearnearthesingleplant,andtheyjustlocateinthepositionsofthedoublepeaksinstream-wisevelocityprofiles.ItisalsofoundthatthevegetationdragcoefficientdeceasesastheFroudenumberincreases.

简介：-Aone-layertime-invarianteddyviscositymodelisspecifiedtodevelopamathematicalmodelfordescribingtheessentialfeaturesoftheturbulentwaveboundarylayeroveraroughbed.Thefunctionalformoftheeddyviscosityisevaluatedbasedoncomputationalresultsfromatwo-equationturbulencemodelinwhichtheeddyviscosityvarieswithtimeandspace.Thepresenteddyviscositymodelsimplifiesmuchofthemathematicalcomplexityinmanyexistingmodels.Predictionsfromthepresentmodelhavebeencomparedwithawiderangeofexperimentaldata.Itisfoundthattheeddyviscositymodeladoptedinthepresentstudyisphysicallyreasonable.

简介：Inthispaperlargeeddysimulationofthefullydevelopedturbulentflowinacurvedchanneliscarriedout.ThecomputationalresultsarepresentedandcomparedwiththeexperimentalresultsofEskinaziandYeh.ItisshownthatthenumericalresultsofthepresentLESarereliableandtheinfluenceofthecurvatureontheturbulencefeatureiscorrectlyrevealed.

简介：TheFilteringGridScale(FGS)ofsub-gridscalemodelsdoesnotmatchwiththetheoreticalProperFGS(PFGS)becauseoftheimpropermesh.Therefore,properLargeEddySimulation(LES)Meshisverydecisiveforbetterresultsandmoreeconomicalcost.Inthiswork,thepurposeistoprovideanadaptivecontrolstrategyforproperLESmeshwithturbulencetheoryandCFDmethods.AnewexpressionofPFGSisproposedonthebasisof-5/3lawofinertialsub-rangeandthepropermeshofLEScanbebuiltdirectlyfromtheadjustmentofRANSmesh.Abenchmarkofthebackwardfacingstepflowatisprovidedforapplicationandverification.Therearethreekindsofmeshsizes,includingtheRANSmesh,LAM(LESofadaptive-controlmesh),LFM(LESoffinemesh),employedhere.ThegridnumberofLAMissmallerthanthoseofLFMevidently,andtheresultsofLAMareinagoodagreementwiththoseofDNSandexperiments.ItisrevealedthattheresultsofLAMareveryclosetothoseofLFM.Theconclusionsprovidepositiveevidencesforthenovelstrategy.

简介：Eddy-currentinversetechniqueisaveryimportantmethodtoreconstructtheshapeofflawsorcracks.Usingthedomainderivativeofthefar-fieldpatternforeddy-currentinverseproblemwithDirichletboundarycondition,anewalgorithmtorecovertheshapeofcrackswasconstructedandsomenumericalexamplesweregiven.Thealgorithmdemonstratesthatthealgorithmisfeasibleandcorrectforobtainingareasonablereconstructionofashapeofflawsorcracksfromthefar-fieldmeasurementseventhoughusinglessdataofdirectionsofincidenceandobservationsforfewerwavenumbersaregived.

简介：在中国上的暴风雪的第三个阶段的energetics用ECWMF数据被分析。为中东马槽和在25282008年1月上向中国发展了的西方的和平的马槽的精力预算的分析由是关键来源和与马槽联系的旋涡动能中心的主要水池的ageostrophic风显示出geopotential的移流。精力变换学期，相互作用动能变换和baroclinic变换的大小，太小，不能解释精力中心和喷气条纹的发展。精力中心经由ageostrophicgeopotential流动的集中在他们的入口区域获得了精力，然后由一样的流动在他们的出口区域失去了精力。在入口区域，流动收敛了，增加geopotential坡度，它产生了更大的因地球自转而引起的风和更高的动能，导致在这个区域的一个上升运动。当马槽搬到中国时，流动的集中在入口区域引起的上升运动在中央、南部的中国上加强了暴风雪。

简介：Athree-dimensional(3-D)oceanmodeliscoupledwithatwo-dimensional(2-D)seaicemodel,torevisitanonlinearadvectionmechanism,oneofthemostimportantmesoscaleeddygenesismechanismsinthemarginalicezone.Two-dimensionaloceanmodelsimulationssuggestnonlinearadvectionmechanismismoreimportantwhenthewatergetsshallower.Insteadofconsideringtheoceanasbarotropicfluidinthe2-Doceanmodel,the3-Doceanmodelallowstheseaicetoaffectthecurrentdirectlyinthesurfacelayerviaocean-iceinteraction.Itisfoundthatbothmesoscaleeddyandseasurfaceelevationaresensitivetochangesinawaterdepthinthe3-Dsimulations.Theverticalprofileofacurrentvelocityin3-Dexperimentssuggeststhatwhenthewaterdepthgetsshallower,thecurrentmovefasterineachlayer,whichmakestheseasurfaceelevationbenearlyinverseproportionaltothewaterdepthwiththesamewindforcingduringthesametime.Itisalsofoundthatbecauseoftheverticalmotion,themagnitudeofvariationsintheseasurfaceelevationinthe3-Dsimulationsisverysmall,beingonly1%ofthechangeinthe2-Dsimulations.Anditseemstheverticalmotiontobetheessentialreasonforthedifferencesbetweenthe3-Dand2-Dexperiments.

简介：Leanpremixedcombustion,whichallowsforreducingtheproductionofthermalNOx,ispronetocombustioninstabilities.Thereisanextensiveresearchtodevelopareducedphysicalmodel,whichallows-withouttime-consumingmeasurements-tocalculatetheresonancecharacteristicsofacombustionsystemconsistingofHelmholtzresonatortypecomponents(burnerplenum,combustionchamber).FortheformulationofthismodelnumericalinvestigationsbymeansofcompressibleLargeEddySimulation(LES)werecarriedout.Intheseinvestigationstheflowinthecombustionchamberisisotherm,non-reactingandexcitedwithasinusoidalmassflowrate.Firstlyacombustionchamberasasingleresonatorsubsequentlyacoupledsystemofaburnerplenumandacombustionchamberwereinvestigated.Inthispapertheresultsofadditionalinvestigationsofthesingleresonatorarepresented.Theflowinthecombustionchamberwasinvestigatedwithoutexcitationattheinlet.Itwasdetected,thatthemassflowrateattheoutletcrosssectionispulsatingoncetheflowinthechamberisturbulent.ThefastFouriertransformofthesignalshowedthatthedominantmodeisattheresonancefrequencyofthecombustionchamber.Thisresultshedslightonaveryimportantsourceofself-excitedcombustioninstabilities.FurthermoretheLEScanprovidenotonlythedampingratiofortheanalyticalmodelbuttheeigenfrequencyoftheresonatoralso.

简介：

简介：源于空气包裹扩大/压缩的密度效果的修正在当开路径的系统被使用时，解释水汽和公司2的旋涡协变性流动是重要的。到为这些效果的报道，干空气的密度的吝啬的垂直速度和不安是在对待为密度变化负责的那些物理进程的二个批评参数。基于各种各样的内在的假设，不同研究为干空气的密度的吝啬的垂直速度和不安获得了不同公式，导致很多条途径改正密度效果。在这研究，我们再考与被做到的不同假设有关的物理过程提出密度效果。明确地，我们覆查零干空气流动的假设和在表面层的零湿空气流动，使用为改正密度效果对待密度变化，和他们的含意。在与零干空气流动的假设的关系的物理过程说明对密度变化的干空气扩大/压缩的影响，这被发现。同时，在与零湿空气流动的假设的关系的物理进程说明对密度变化的湿空气扩大/压缩的影响。在这研究，我们另外覆查混合比问题。我们的结果显示零干空气流动的假设相对干空气赞成混合比的使用，当零湿空气流动的假设相对全部的湿空气赞成混合比的使用时。另外，我们为吝啬的垂直速度比较不同公式，由空气包裹扩大/压缩产生了，并且为使用的密度效果修正，旋涡协变性数据测量了超过三个北方的生态系统。

简介：Alargeeddysimulation(LES)oftheflowsaroundanunderwatervehiclemodelatintermediateReynoldsnumbersisperformed.TheunderwatervehiclemodelistakenastheDARPASUBOFFwithfullappendages,wheretheReynoldsnumberbasedonthehulllengthis1.0×105.Animmersedboundarymethodbasedonthemoving-least-squaresreconstructionisusedtohandlethecomplexgeometricboundaries.Theadaptivemeshrefinementisutilizedtoresolvetheflowsnearthehull.Theparallelscalabilitiesoftheflowsolveraretestedonmesheswiththenumberofcellsvaryingfrom50millionto3.2billion.Theparallelsolverreachesnearlylinearscalabilityfortheflowsaroundtheunderwatervehiclemodel.Thepresentsimulationcapturestheessentialfeaturesofthevortexstructuresnearthehullandinthewake.Bothofthetime-averagedpressurecoefficientsandstreamwisevelocityprofilesobtainedfromtheLESareconsistentwiththecharacteristicsoftheflowspassanappendedaxisymmetricbody.Thecodeefficiencyanditscorrectpredictionsonflowfeaturesallowustoperformthefull-scalesimulationsontensofthousandsofcoreswithbillionsofgridpointsforhigher-Reynolds-numberflowsaroundtheunderwatervehicles.

简介：Thisstudyaimstoexploregenerationmechanismsoftheoceaninternalwaveusingthedynamicalanalysismethodsbasedonlineartheories.Historicalcruisemeasurementsandrecentsyntheticapertureradar(SAR)observationsofmesoscaleeddieswithdiameterofseveraltensofkilometerstohundredsofkilometersshowthattheinternalwavepacketswithwavelengthofhundredsofmeterstokilometerexistinsidethemesoscaleeddies.Thiscoexistencephenomenonandinherentlinksbetweenthetwodifferentscaleprocessesarerevealedinthesolutionsofgoverningequationsandboundaryconditionsfortheinternalwavedisturbancewithahorizontallyslowlyvariableamplitudeinacylindricalcoordinatesystem.Thetheoreticalsolutionsindicatethattheinstabilityofeddycurrentfieldprovidesthedynamicalmechanismtointernalwavegeneration.Thederiveddispersionrelationindicatesthattheinternalwavepropagationismodifiedbytheeddycurrentfieldstructure.Theenergyequationoftheinternalwavesclearlyshowstheinternalwaveenergyincrementcomesfromtheeddy.Thetheoreticalmodelsareusedtoexplaintheobservationofthemesoscaleeddy-inducedinternalwavesofftheNorwegiancoast.Thetwo-dimensionalwaveformsolutionoftheanticycloniceddy-inducedinternalwavepacketappearsasring-shapedcurves,whichcontainsthetypicalfeaturesofeddystreamlines.ThecomparisonoftheoreticalsolutionstothestructureoftheinternalwavepacketsonSARimageshowsagoodagreementonthemajorfeatures.

简介：Inthispaper,weinvestigatethefiniteelementA-φmethodtoapproximatetheeddycurrentequationswithdiscontinuouscoefficientsingeneralthree-dimensionalLipschitzpolyhedraleddycurrentregion.Nonmatchingfiniteelementmeshesontheinterfaceareconsideredandoptimalerrorestimatesareobtained.

简介：19最后入缸的是最大的只鱼．蛇纹七彩“霸王”，一听这个名字．就知道EDDY对它寄予了厚望，但非常不幸的是“霸王”入缸之后的表现实在是有负它的名号，整天被“小卓”追着打，让EDDY生气的是霸王居然一点部不敢还手，简直就是个受气包。