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简介:为测量处理方法的一幅图象即时二维(2D)在高水泡数字密度的本地空部分被建议。它基于计算在水泡羽毛图象和真实空部分的局部地平均的亮度之间的关联。方法从设想的图象用本地空部分的2D分发被测试,在在局部地平均的亮度和设计虚空部分之间的关联被在各种各样的条件下面介绍水泡图象的重叠概率的理想导出的地方。这研究被用来与方面比率of1.0学习冒泡的流动的行为1.5,和2.0。现在的方法被用于即时测量。为有产生流动率的三个不同水泡的三不同方面比率的水泡羽毛的空部分在冒泡的流动的行为上为水泡的效果的澄清被测量。煤气的流动率上的空部分的相关性被测量并且与其它相比源于文学。在我们的实验的范围,坦克的方面比率不仅影响羽毛的结构,而且在坦克的煤气的流动率影响羽毛的结构,这被观察。
简介:NUMERICALSTUDYOFTURBULENTJETSCONFINEDBETWEENTWOCONCENTRICSPHERESZhangGuang-hua;TangGe-feng(TsinghuaUniversity,Beijing,100084,...
简介:THELINEARSEPARATEDFLOWMODELFORTWO-PHASIFLOWINSTABILITYINBOILINGCHANNELS¥ZhouYun-long;ShenZeng-ming;ShiHui-xian(NortheastChina...
简介:Flow-inducedvibrationoftwocircularcylindersintandemarrangementelasticallymountedwithamass-spring-dampingsystemwasstudiedbysolvingtheprimitivevariableNavier-StokesequationsincorporatingtheArbitraryLagrangian-Eulerian(ALE)method.Theconvectiontermanddissipationtermwerediscretizedusingthethird-orderupwindcompactschemeandthefourth-ordercentralcompactscheme,respectively.Thetypicalspacingbetweenthecylindersis4diameters,whichisclosetothecriticalvalue.Thedynamicresponseofthevibrationsontwocylinderswithtwo-degree-of-freedommotionisdifferentfromthatofanisolatedcylinder,andalsodifferentfromthatofacylindervibratinginthewakeofafixedupstreamone.Differentflowpatternswerefoundinthewake,andprovedtoberelevanttothediscontinuitiesobservedintheresponseoftheoscillatorycylinders.
简介:Thispaperisconcernedwiththewavesgeneratedbya3-Dbodyadvancingbeneaththefreesurfacewithconstantspeedinatwo-layerfluidoffinitedepth.ByapplyingGreen'stheorem,alayeredintegralequationsystembasedontheRankinesourcefortheperturbedvelocitypotentialgeneratedbythemovingbodywasderivedwiththepotentialflowtheory.Afour-nodeisoparametricelementmethodwasusedtotreatwiththesolutionofthelayeredintegralequationsystem.Thesurfaceandinterfacewavesgeneratedbyamovingballwerecalculatednumerically.Theresultswerecomparedwiththeanalyticalresultsforamovingsourcewithconstantvelocity.
简介:Takingaccountofturbulenceintensity,non-uniformityofvelocitydistributionattheinitialandsequentsec-tionofhydraulicjumpandfrictionaldragonthefloorwithinjumprange,thispaperderivesnewformulasforcal-culatingtheratioofconjugatedepthsandtheefficiencyofenergydissipationinthetwo-dimensionalfreehydraulicjump.Ithasbeenverifiedbytestdatathatthenewformulasarenotonlyexactintheorybutalsostillbetterinconformitywithpractice.
简介:ExperimentalStudyonoil-watertwo-phaseflowpatternsandpressurelosswasconductedonahorizontalsteelpipeloopwith26.1mminnerdiameterand30mtotallength.Theworkingfluidsarewhiteoil,dieseloilandtapwater.Severalinstruments,includinganewtypeofliquid-probearesuccessfullyintegratedtoidentify7differentflowpatterns.Thecharacteristicsoftheflowpatternsandthetransitionprocesswereobservedanddepictedinthispaper.Investigationrevealedthatthepressurelosswasmainlydependedontheflowpatterns.
简介:Twonear-fieldmethods,namelytheintegralmethodanddifferentialmethod,werepresentedforgivingsecond-ordermeandriftforcesandmomentsbetweentwofixedsubmergedbodiesinregularwaves.Fortheintegralmethod,withaseriesofmathematicalmanipulations,second-orderdriftforcesandmomentscouldbeeasilyexpressedbydistributedsourceswhichcouldbecalculatedbysourcedistributiontechniqueswiththeassumptionthattheamplitudeofshipmotionsaresmallonthebasisofthelinear3Dfrequencytheory.Forthedifferentialmethod,driftforcesandmomentscouldbeexpressedbythederivativeofvelocitypotentialwithrespecttospacecoordinate.Becausetwobodieswouldbehaveasasinglebodywhiletheclearanceisverylarge,thenumericalresultsofonesphereinsuchcaseweregivenandcomparedwithanalyticalresultsofasinglespherewhichdoesnotinvolvetheeffectoffreesurface.Whensubmergeddepthbecomesenoughlarge,agoodagreementcanbereached.Thentheintegralmethodwasusedtopredictthesecond-orderdriftforcesandmomentsoftwosubmergedspheresandspheroidswithasmalllateralseparationdistanceinwavescomparedwiththenumericalresultsobtainedbythedifferentialmethodandtheyagreewell.Bycomparison,itindicatestheinteractioneffectsbetweentwosubmergedbodieshaveaprofoundinfluenceonthedriftforcesandmoments.Inthispaper,theforwardspeedeffectonsubmergedsphereswasalsoconsidered.
简介:Thepapermainlyfocusesondescribingthemodificationmadetoanewdepth-averagedtwo-equationturbulentclosuremodelbasedontherevisedκ-ωmodelrecently.Inthecaseofsidedischargedjetswithtempera-turedifferenceandtransversecurrent,thenewmodelhasbeeninvestigatednumericallyindetail.Asapracticalexampleofapplicationtousethenewmodel,thesidedischargeofthecoolingwaterfromthreeoutletsintoanatu-ralriverononebankhasbeensimulated,andthegeomorphicvariationunderwaterhasbeentreatedsuitably.Twodepth-averagedmodels,andhavebeenused,thelaterwastheuniqueoneuptothepresent.Emphasisisplacedonthecomparativeresearchwithdifferentmodelsunderthesamecomputationalconditions.Ithasbeenverifiedthatifthedischargedflowratesarerelativelysmall,whenthepollutantplumeinthenearandtransitionalzonsispredicted,theagreementwithexperimentalandfielddatasimulatedbythemodelisbetterthanbythemodelorothermethodscommonlyusedinengineering.