简介：Theelementalmechanismsformanyhydrodynamicinstabilitiescanbeidentifiedasnegativedamping,negativediffusionorellipticity.Identificationsofsomewell-knownhydrodynamicinstabilitiesaremade.Modelequationsinconnectionwiththeinstabilityassociatedwithellipticityshouldbestudiedmoreextensively.

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

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简介：Inthispaper,thehydrodynamiccharacteristicsofwaterflowinChaohuLakearestudiedbyusingthefinitevolumecoastaloceanmodel(FVCOM),whichisverifiedbytheobserveddata.Thetypicalflowfieldandthe3-Dflowstructureareobtainedforthelake.Theflowfieldsunderextremeconditionsareanalyzedtoprovideaprospectiveknowledgeofthewaterexchangeandthetransportprocess.Theinfluenceofthewindontheflowisdeterminedbythecrossspectrummethod.Theresultsshowthatthewind-drivenflowdominatesmostareaofthelake.Underprevailingwindsinsummerandwinter,thewaterflowstowardsthedownwindsideattheupperlayerwhiletowardstheupwindsideatthelowerlayerinmostareaexceptthataroundtheChaohuSluice.Theextremewindspeedisnotfavorableforthewaterexchangewhilethesluice’sreleasingwateracceleratestheprocess.Thewatervelocityinthelakeiscloselyrelatedwiththewindspeed.

简介：Asemi-implicitandEulerian-Lagrangianfinitedifferencemethodforthree-dimensionalshallowflowhasbeenextendedtoamorecompletesystemofequationsincorporatingsecond-momentturbulenceclosuremodelandtransportequationsofsalinityandtemperature.Thesimulationforfloodinganddryingofmudflatshasbeenimproved.ThemodelisappliedtoXiamenwaters.Basedonextensivesurveydata,waterlevelelevation,temperatureandsalinityfieldalongtheeasternopenboundaryandattheJiulongRiverinletsandrunoffsareanalyzed,specifiedandcalibrated.Thecomputedresultsshowgoodagreementwiththemeasureddata,reproduceflooding,emergenceoflargeandcomplexmudflatregion.

简介：-Inordertoemploycosteffectivefrequencydomainanalysisforoff-shorestructurestreatmentofhydrodynamicloadingisessential.Dragandinertiadominated,resonatingandantiresonatingcasesunderrandomseastatesareanalyzedtohighlighttheimplicationsandrelativemeritsoffoursalientlinearizationtechniques.

简介：以便，水的动物的稳定的鳗状的游泳运动才是完全反应的没有网旋涡醒来被让下游。这是对在旋涡流的地方，鱼游泳的carangiform和tunniform是从尾巴，鳍，和身体流。但是在那里，动物运动是这在最大化推进的效率下游地生产部分旋涡取消。在鳗家庭的鳗状的游泳特征，以便旋涡流根本不发生，游泳运动才被动物设置。然而，在这种情况中的推进的戳是在运动振幅的更高的顺序，以便相对大的卷被需要生产相对小的戳；鳗状的游泳者的速度不到carangiform和tunniform，它首先发展经由提起过程订戳。实时七鳃鳗上的试验的结果与假定没有醒来假设的理论预言相比。二维的分析首先被执行设置这个概念。这被三维的分析用苗条身体的理论跟随。苗条身体的理论被其它在学习鳗状的游泳使用了，当它理想地被适合到七鳃鳗和另外的似鳗的动物的几何学。尽管有物理复杂性，在这条新途径之间的协议基于wakeless游泳和实验的假设显著地好。

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简介：Thispaperaimsatinvestigationofthedynamicpropertiesofgravitycageexposedtowavesbyuseofanumericalmodel.Thenumericalmodelisdeveloped,basedonlumpedmassmethodtosetuptheequationsofmotionofthewholecage;meanwhilethesolutionsofequationsaresolvedbytheRunge-Kutta-Vernerfifth-orderandsixth-ordermethod.Physicalmodeltestshavebeencarriedouttoexaminethevalidityofthenumericalmodel.Theresultsbythenumericalsimulationagreewellwiththeexperimentaldata.

简介：这研究检验多重排的垂直slotted防波提的水动力学表演。我们基于一个特徵函数扩大方法和一种最少的广场技术开发了一个数学模型为司烧秒顺序波浪。为限制双排和三倍排的墙的格获得的数字结果在对以前的研究的结果和试验性的结果的好同意。有思考，传播，和驱散系数的试验性的大小的比较(为双排墙的CR,CT,和CE)证明建议数学模型足够地复制大多数重要特征。我们发现为双排墙，有增加的CR增加挥动数字，kd，并且与减少可渗透的墙部分，dm。CT跟随相反的趋势。CE慢慢地为更低的kd价值与增加的kd增加，到达最大值，然后再减少。另外，dm的一个增加的孔将显著地减少CR,当增加CT时。在kd的更低的价值，一个减少的孔要不是kd的高价值增加CE,，一个减少的孔减少CE。数字结果显示为三倍排的墙，水动力学特征上的房间宽度的安排的效果不是重要的，除了当时kd<0.5。双排slotted防波提可以在kd展出好吸收波浪的表演>0.5，在由水平波浪力量可能比一个单身者的小的地方，围。在另一方面，双排之间的差别和三倍排的垂直slotted防波提是边缘的。

简介：Hydrodynamicinstabilityandthemechanismsforturbulenceonsetandself-sustainingaretworesearchquestionsthathavepuzzledthescientistsforoveracentury,yetrenewedinterestandsignificantprogressoccurredinthelastdecadeorso.WeknowonlyfewexactanalyticalsolutionsoftheNavier-Stokesequations,theequationsgoverningtheflowofsimplefluidslikewaterandair,andmostoftheseareneverobservedinapplicationsorlaboratory

简介：ThekinematicsofturningmaneuversofstartledCrucianCarp(Carassiusauratus)arepresented.AllescaperesponsesobservedareC-typefast-starts.Thepositionofthecenterofmassandthemomentofinertiaofthefisharecalculated.Theresultsshowthatthepositionofthecenterofmassisalwaysat35%ofthelengthofthefishfromtheheadandthepositionofthecenterofmassandmomentofinertiacanbeconsideredunchangedduringC-startofCrucianCarp.HydrodynamicanalysisoftheC-startisgivenbasedonthekinematicsdatafromourexperiments.TheC-startconsistsofthreestages.Instage1,thetailfinoffishrapidlyflapsinonedirection,andalargemomentactsonthefish'sbody,whichrotatesaroundthecenterofmasswithanangularacceleration.Instage2,thetailfinflapsmoreslowlyintheoppositedirectionatslowerspeed,thefish'sbodyrotatesaroundthecenterofmasswithangulardecelerationandthecenterofmassofthefishmovesalonganarc.Instage3,themomentapproximatelyequalszero,thefish'sbodystopsrotatingandthecenterofmassthemovesalongastraightline.

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简介：Inthispaper,wepayattentiontothetime-decayrateoftheviscousbipolarquantumhydrodynamic(QHD)modelsforsemiconductors.Byapplyingtheentropymethod,weprovethatthesolutionoftheviscousbipolarQHDmodelstendstotheequilibriumstateatanexponentialdecayrateforthemulti-dimensionalcases.Theargumentsisbasedonaseriesofaprioriestimates.

简介：灵活圆形的柱体的导致流动的颤动(FIV)上的集体比率的效果试验性地在一辆拖引的坦克被调查。分别地，有7.9公里和4.8公里的外部、内部的直径的一个Tygon试管为学习被采用。试管被连接到一辆马车并且从休息拖引到一稳定在慢下来在1.6m的距离上再休息在前加快m/s到1.6仍然流水。雷纳兹数字基于柱体，外部直径是80013,000，并且减少的速度(柱体天赋频率使正常化的速度和外部直径)从2～25跨越了。当连接时，柱体在11N的轴的虚荣下面从420公里被伸长到460公里。把伸长的长度基于柱体，方面比率(到外部直径的柱体长度的比率)作为58被计算。三集体比率(柱体的比率结构的质量到代替的液体质量，m*)被分别地用空气，水，和合金粉末(nickel-chromium-boron矩阵合金)填满柱体内部0.7，1.0，和3.4决定。一个光方法为反应大小被采用。多频率颤动在两个被观察同轴(IL)并且跨流动(CF)回答；在高级雷纳兹数字，颤动模式直到3rd在CF反应被识别。模式转变被发现为最高测试的集体比率在更低的减少的速度发生。颤动振幅和频率关于减少的速度被确定并且表示。一个重要减少的颤动振幅与增加集体比率在IL反应被发现，并且仅仅起始、上面的分支在IL和CF反应振幅存在。规范的反应频率被揭示线性地关于减少的速度增加，并且为线性关系的斜坡被发现为测试的三格相同。

简介：-ThehydrodynamicforcesonasmoothinclinedcircularcylinderexposedtooscillatingflowwereexperimentallyinvestigatedatReynoldsnumber(Re)intherange40000-200000andKeulegan-Capenternumber(KC)intheintervalfrom5-40.Inthetest,RenumberandKCnumberwerevariedsystematically.Theinertiaforcecoefficient(Cu)andthedragforcecoefficient(CD)inMorisonequationweredeterminedfromthemeasuredloadsandthewaterparticlekinematics.InthisanalysisamodifiedformofMorisonequationwasusedsinceitusesthenormalvelocityandacceleration.Thus,theapplicabilityoftheCrossFlowPrinciplewasassumed.Thisprinciple,simplystated,isasfollows:theforceactinginthedirectionnormaltotheaxisofacylinderplacedatsomeobliqueanglewiththedirectionofflowisexpressedintermsofthenormalcomponentofflowonly,andtheaxialcomponentisdisregarded.Boththetotalin-lineforcecoefficient(CF)andtransverseforce(lift)coefficient(Cf)wereanalyzed

简介：Anefficientmulti-blockincompressibleviscousflowsolverbasedonsolvingtheReynolds-AveragedNavier-Stokes(RANS)equationsnumericallyhasbeendevelopedthatcanbeappliedtosimulationofavarietyofshipmaneuveringrelatedflowsandcalculationofhydrodynamicforces.Validationandverificationofthesolutionprocedurewerecarriedoutonseveralmodelproblemswithgoodagreementtoexperimentalandnumericalresults.

简介：TheVenturi-roddecktrayisatypeofdualflowtraysusedinfluegasdesulfurization(FGD)process.Inthispaper,thehydrodynamiccharacteristicsoftheVenturi-roddecktraywerestudiedintheexperimentsandcomparedwiththeconventionalsievetray.Resultsshowedtheturndownratioofthistraywasintherangeof2.71-3.77,whichwasby9%higherthanthesievetray.Besides,thepressuredropofthistraywasbymorethan50%lowerthanthesievetray.Basedontheexperimentaldata,thecorrelationfunctionsforthepressuredropandthefrothheight,respectively,wereobtained.TheindustrialscaleuppracticeofthistrayinFGDprocesswasdescribedwiththeefficiencyofthistraydemonstrated.

简介：-Thehydrodynamiccoefficientsforeachoftwopilesandthreepilesinbothside-by-sidearrangementandtandemarrangementundertheactionofirregularwavesareexperimentallyinvestigated.ThesecoefficientsvarywiththeKCnumber,therelativepilespacing,thenumberofpilesandthepilelocation,andtheirrelationshipsarepresentedinthispaper.TheycanbeusedinMorisonEquationandotherequationstocalculatedirectlythein-linewaveforcesandthetransverseforcesoneachpileinarray.

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