简介：Onthebasisofmodeltests,potentialflowtheory,andviscousComputationalFluidDynamics(CFD)method,thehydrodynamicinteractionsbetweentwounderwaterbodieswereinvestigatedtodeterminetheinfluencingfactors,changingrule,interactionmechanism,andappropriatemethodsdescribingthem.Somespecialphenomenawerediscoveredintwoseriesofnear-wallinteractionexperiments.Themathematicalmodelandpredictingmethodswerepresentedforinteractingforcesnearwall,andthecalculationresultsagreedwellwiththeexperimentalones.Fromthecomparisonsamongnumericalresultswithrespecttononviscosity,numericalresultswithrespecttoviscosity,andmeasuredresults,dataontheinfluenceofviscosityonhydrodynamicinteractionswereobtained.Forhydrodynamicinteractionrelatedtomulti-bodyunsteadymotionswithsixdegreesoffreedomthatisdifficulttosimulateintests,numericalpredictionsofunsteadyinteractingforcesweregiven.

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：Thisstudyproposesanewelectromagneticrectangularmixer,andnumericallyexaminesthemixingcharacteristicsoftwodifferentelectrolytesolutionsinthedeviceunderauniformmagneticfield.Themixerconsistsofaconduitwithelectrodesequippedonitstopandbottomwalls.Thedifferenceintheelectricpotentialsappliedtothesetsofelectrodesinducesthecurrent.ThecombinationoftheinducedcurrentandmagneticfieldyieldsLorentzforce,resultinginthefluidmotionforpumpingandmixingofthetwodifferentfluids.ThenumericalsimulationiscarriedoutwiththeuseofcommercialsoftwareCFX.Thepresentnumericalmodelisvalidatedbyanexistingnumericalwork.Theeffectofdifferentvariablesonmixingefficiencyisinvestigatedinmanydifferentcaseswithtwodifferentheightsoftheductandvariousinputvoltagesoftheelectrodes.Thecurrentsimulationresultsindicatethatthemixingperformancecanbeenhancedbyusingmultiplesetsofelectrodesandapplyinghigherinputvoltages(absolutevalues)totheelectrodes.

简介：Thequasi-2Dmodel,takingintoaccounttheaxialvelocityprofileinthecrosssectionandneglectingtheconvectiveterminthe2-Dequation,canmoreaccuratelysimulatethewaterhammerthanthe1-Dmodelusingthecross-sectionalmeanvelocity.However,ascomparedwiththe1-Dmodel,thequasi-2Dmodelbearsahighercomputationalburden.Inordertoimprovethecomputationalefficiency,the1-Dmethodisproposedtobeusedtosolvedirectlythepressureheadandthedischargeinthequasi-2Dmodelinthispaper,basedonthefactthatthepressureheadobtainedasthesolutionofthetwo-dimensionalcharacteristicequationisidenticaltothatsolvedbythe1-Dcharacteristicequations.Theproposedschemesolvesdirectlythe1-DcharacteristicequationsforthepressureheadandthedischargeusingtheMOCandsolvesthe2-Dcharacteristicequationfortheaxialvelocitiesinordertocalculatethewallshearstress.Iftheradialvelocityisneeded,itcanbeevaluatedeasilybyanexplicitequationderivedfromtheexplicit2-Dcharacteristicequation.Inthenumericaltest,theaccuracyandtheefficiencyoftheproposedschemearecomparedwithtwoexistingquasi-two-dimensionalmodelsusingtheMOC.Itisshownthattheproposedschemehasthesameaccuracyasthetwoquasi-2Dmodels,butrequireslesscomputationaltime.Therefore,itisefficienttousetheproposedschemetosimulatethe2-Dwaterhammerflows.

简介：ＮＵＭＥＲＩＣＡＬＳＴＵＤＹＯＦＴＵＲＢＵＬＥＮＴＪＥＴＳＣＯＮＦＩＮＥＤＢＥＴＷＥＥＮＴＷＯＣＯＮＣＥＮＴＲＩＣＳＰＨＥＲＥＳＺｈａｎｇＧｕａｎｇ－ｈｕａ；ＴａｎｇＧｅ－ｆｅｎｇ（ＴｓｉｎｇｈｕａＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎｇ，１０００８４，...

简介：Inthisarticle,the2-Dunsteadyviscousflowaroundtwocircularcylindersinatandemarrangementisnumericallysimulatedinordertostudythecharacteristicsoftheflowinbothlaminarandturbulentregimes.ThemethodappliedalternativelyisbasedonthefinitevolumemethodonaCartesian-staggeredgrid.Thegreatsourcetermtechniqueisemployedtoidentifythecylindersplacedintheflowfield.Toapplytheboundaryconditions,theghost-celltechniqueisused.Theimplementedcomputationalmethodisfirstlyvalidatedthroughsimulationoflaminarandturbulentflowsaroundafixedcircularcylinder.Finally,theflowaroundtwocircularcylindersinatandemarrangementissimulatedandanalyzed.Theflowvisualizationparameters,theStrouhalnumbers,anddragandliftcoefficientsarecomprehensivelypresentedandcomparedfordifferentcasesinordertorevealtheeffectoftheReynoldsnumberandgapspacingonthebehavioroftheflow.Theobtainedresultshaveshowntwocompletelydistinctflowcharacteristicsinlaminarandturbulentregimes.

简介：ＳＯＬＵＴＩＯＮＯＦＲＥＬＡＴＩＶＥＰＥＲＭＥＡＢＩＬＩＴＹＯＦＴＷＯ－ＰＨＡＳＥＦＬＯＷＩＮＰＯＲＯＵＳＭＥＤＩＵＭＬｕＹｕ－ｌｉｎ（ＩｎｓｔｉｔｕｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉｃｓ，ＤａｌｉａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇ...

简介：为在调查的飘动的plateare附近的二维的流动的水动力学特征。在大雷纳兹数字近似下面，流动被假定是combinationof外部潜在的流动和薄旋涡层，它由边界层和shedfree组成砍层。为描述外部不稳定的potentialflow的非线性的数学明确的表达结合了一个不稳定的边界层方程为内部粘滞邻近thewaving板的流动被开发。有在thetrailing边强加的一个非线性的Kutta条件的一个半分析的方法被用来解决外部流动和进化的速度领域由一个大振幅的飘动盘子弄醒vortexinduced。不稳定的边界层方程是解决的byextendingPohlhausen“s方法到它的不稳定的对应物。戳并且粘滞拖系数，推进的效率，和模式醒来旋涡表被讨论。

简介：Theflowbetweentwocoaxialconicalcylindersisnumericallystudiedfortwodifferentconfigurations,withtheinnerconerotatingandtheouteroneatrest.Itisfoundthat,inoneconfiguration,atleastatasmallReynoldsnumber(Re),thepressureisadecreasingfunctionofzwhileintheotherconfiguration,itisanincreasingfunctionofz.Inthefirstconfiguration,thepressurecurvesfordifferentRehaveintersections,whileinthesecondconfigurationtheydonot.ThegapbetweentwoconicalcylindersisfilledwithsixpairsofTaylorvorticesataboutthesameReynoldsnumberandineachpairofvorticesinthefirstconfiguration,theuppervortexislargerthanthebottomonewhileinthesecondconfiguration,thebottomvortexislargerthantheupperone.

简介：ＴＨＥＬＩＮＥＡＲＳＥＰＡＲＡＴＥＤＦＬＯＷＭＯＤＥＬＦＯＲＴＷＯ－ＰＨＡＳＩＦＬＯＷＩＮＳＴＡＢＩＬＩＴＹＩＮＢＯＩＬＩＮＧＣＨＡＮＮＥＬＳ￥ＺｈｏｕＹｕｎ－ｌｏｎｇ；ＳｈｅｎＺｅｎｇ－ｍｉｎｇ；ＳｈｉＨｕｉ－ｘｉａｎ（ＮｏｒｔｈｅａｓｔＣｈｉｎａ...

简介：

简介：1-Dand2-Dmathematicalmodelsfordambreakflowwereestablishedandverifiedwiththemeasureddatainlaboratory.The1-Dand2-Dmodelswerethencoupled,andusedtosimulatethedambreakflowfromthereservoirtailtothedamsite,thepropagationofdambreakwavesinthedownstreamchannel,andthesubmergenceofdambreakflowinthedownstreamtownwiththehydrodynamicsmethod.Asanumericalexample,thepresentedmodelwasemployedtosimulatedambreakflowofahydropowerstationunderconstruction.Insimulation,differentdam-breakdurations,upstreamflowsandwaterlevelsinfrontofdamwereconsidered,andtheseinfluencingfactorsofdambreakflowwereanalyzed,whichcouldbereferencedinplanninganddesigninghydropowerstations.

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：Thetransientgravitywavesduetoanimpulsivesourceinatwo-layerfluidsystemareinvestigatedanalytically.Thefluidisassumedtobeinviscidandincompressible.Thedensityofeachofthetwolayersisconstant.Fivedifferentboundaryconditionsareconsidered.Thedepthofeachofthetwolayersisinfiniteorfinite.Theupperfluidoffinitedepthiscoveredbyarigidlidorafreesurface.Basedontheassumptionofsmall-amplitudewaves,alinearsystemisestablished.Theintegralsolutionsforthefree-surfaceandinterfacialwavesareobtainedbymeansoftheFourier-Laplacetransform.Thecorrespondingasymptoticrepresentationsarederivedforlargetimewithafixeddistance-to-timeratiobytheStokesandScorermethodsofstationaryphase.Theanalyticalsolutionsshowthattherearetwodifferentmodes,namelythefree-surfaceandinterfacialwavemodes.Thewaveprofilesobserveddependontherelationbetweenthedistance-to-timeratioandthemaximalgroupvelocitiesandonthelimitingvaluesofthesecondderivativesofthefrequenciesaswell.

简介：Theflowaroundtwoplateshavingasymmetricbeveledtrailingedgeplacedside-by-sideinauniformstreamwereinvestigatedbothnumericallyandexperimentally.Twoplateswithspacingratioof1.0andbeveledtrailingedgeofangle20oweretestedatReynoldsnumbersequalto3.97×104.Thenumericalsimulationresultsdisplayedthattheflowseparatesononeplatebeveledtrailingedgesurface.Thevortexformationandsheddingfromthisplateledtodeflectingtheflowtowardtheotherplateandconsequentlythewakebehindtheplatesshowedanasymmetricdevelopment.Thephotographsobtainedfromtheflowvisualizationconfirmedthenumericalresultsconcerningtheflowseparationandvortexformation.Itwasalsofoundthatthecomputedpressuredistributiononthetwoplatesurfaceswasdifferent,particularlyonthebeveledtrailingedgesurfacesandontheflatsides.

简介：Thispaperisconcernedwiththewavesgeneratedbya3-Dbodyadvancingbeneaththefreesurfacewithconstantspeedinatwo-layerfluidoffinitedepth.ByapplyingGreen'stheorem,alayeredintegralequationsystembasedontheRankinesourcefortheperturbedvelocitypotentialgeneratedbythemovingbodywasderivedwiththepotentialflowtheory.Afour-nodeisoparametricelementmethodwasusedtotreatwiththesolutionofthelayeredintegralequationsystem.Thesurfaceandinterfacewavesgeneratedbyamovingballwerecalculatednumerically.Theresultswerecomparedwiththeanalyticalresultsforamovingsourcewithconstantvelocity.

简介：一个分析方法被建议在二层的液体由装底部的圆形的柱体分析放射和衍射ofwater波浪。分析表情foradded质量和抑制系数，以及圆形的cylinderwere的波浪刺激力量由一个特徵函数扩大方法获得了。在二层的液体的bottom-mountedcircular柱体上的水动力学力量包括不仅增加的团和抑制系数，butalso表面的波浪力量和内部波浪的模式。这与ahomogenous液体的盒子不同。一些例子被给，证明密度层化能有在大量频率上的这些水动力学力量上的relativelarge效果。

简介：Takingaccountofturbulenceintensity,non-uniformityofvelocitydistributionattheinitialandsequentsec-tionofhydraulicjumpandfrictionaldragonthefloorwithinjumprange,thispaperderivesnewformulasforcal-culatingtheratioofconjugatedepthsandtheefficiencyofenergydissipationinthetwo-dimensionalfreehydraulicjump.Ithasbeenverifiedbytestdatathatthenewformulasarenotonlyexactintheorybutalsostillbetterinconformitywithpractice.

简介：Basedonvariationaladjointmethods,theoreticalanalysesandnumericalexperimentsareperformedforretrievalsoftwo-dimensionalwindsandrelatedparametersfromsingle-Dopplerradardatainpolarcoordinates.Inthemethod,thereflectivityconservationequationisusedasthegoverningequationandthemasscontinuityequationasaweakconstraint.Atthesametime,thestablefunctionalofregularizationandbackgroundfieldarealsointroducedinthecostfunctional.Basedontheidealexperimentswithartificialdata,realtwo-dimensionalwindfieldsareretrievedwithlow-altitudedatafromtheNanjingDopplerRadarStation,andtheresultsareencouragingandpromising.

简介：ExperimentalStudyonoil-watertwo-phaseflowpatternsandpressurelosswasconductedonahorizontalsteelpipeloopwith26.1mminnerdiameterand30mtotallength.Theworkingfluidsarewhiteoil,dieseloilandtapwater.Severalinstruments,includinganewtypeofliquid-probearesuccessfullyintegratedtoidentify7differentflowpatterns.Thecharacteristicsoftheflowpatternsandthetransitionprocesswereobservedanddepictedinthispaper.Investigationrevealedthatthepressurelosswasmainlydependedontheflowpatterns.