简介：床负担的数量是在沉积运输研究的一个重要物理参数。在床负担测量瞄准困难，这篇论文开发一个装底部的监视器由采用沉积坑方法并且解决象称和desilting的如此的关键问题测量床负担运输率，它能完成长期，平凡的河，河口和海岸的床负担运输率的全天候、即时的telemeasurement。实验室和这个监视器是合理的在的领域测试表演设计，在性质稳定、方便在里面测量，和它能被用来在实际工程监视床负担运输率。

简介：TosolvethenumericaldivergenceproblemofthedirecttimedomainGreenfunctionmethodforthemotionsimulationoffloatingbodieswithlargeflare,atimedomainhybridRankine-Greenboundaryelementmethodisproposed.Inthisnumericalmethod,thefluiddomainisdecomposedbyanimaginarycontrolsurface,atwhichthecontinuousconditionshouldbesatisfied.ThentheRankineGreenfunctionisadoptedintheinnerdomain.ThetransientfreesurfaceGreenfunctionisappliedintheouterdomain,whichisusedtofindtherelationshipbetweenthevelocitypotentialanditsnormalderivativefortheinnerdomain.Besides,thevelocitypotentialatthemeanfreesurfacebetweenbodysurfaceandcontrolsurfaceisdirectlysolvedbytheintegrationscheme.Thewaveexcitingforceiscomputedthroughtheconvolutionintegrationwithwaveelevation,byintroducingtheimpulseresponsefunction.Additionally,thenonlinearFroude-Krylovforceandhydrostaticforce,whichiscomputedundertheinstantaneousincidentwavefreesurface,aretakenintoaccountbythedirectpressureintegrationscheme.Thecorrespondingnumericalcomputercodeisdevelopedandfirstusedtocomputethehydrodynamiccoefficientsofthehemisphere,aswellasthetimehistoryofashipwithlargeflare;goodagreementisobtainedwiththeanalyticalsolutionsaswellastheavailablenumericalresults.ThenthehydrodynamicpropertiesofaFPSOarestudied.Thehydrodynamiccoefficientsagreewellwiththeresultscomputedbythefrequencymethod;theinfluenceofthetimeintervalandthetruncatedtimeisinvestigatedindetail.

简介：Accuratedeterminationofflushingtimeiscrucialformaintainingsustainableproductioninfishculturezones(FCZs),asitrepresentsthephysicalself-purificationcapabilityviatidalexchangewithcleanwaterintheoutersea.However,owingtothetemporalandspatialcomplexityofthecoastalflushingprocess,existingmethodsfordeterminingflushingtimemaynotbegenerallyapplicable.Inthispaper,asystematicmethodfordeterminingtheflushingtimeinFCZsispresented,inwhichbathymetry,runoff,tidalrangeandstratificationareproperlyaccountedfor.Wedeterminetheflushingtimevianumericaltracerexperiments,usingrobust3Dhydrodynamicandmasstransportmodels.ForFCZslocatedinshelteredandland-lockedtidalinlets,thesystemboundarycanbenaturallydefinedattheconnectionwiththeopensea.ForFCZslocatedinopenwaters,hydrodynamictrackingisfirstusedtoassesstheextentoftidalexcursionandthusdelimittheinitialboundarybetweencleanwaterandpollutedwater.ThisgeneralmethodisappliedtoalldesignatedmarineFCZsinHongKongforboththedryandwetseasons,including20shelteredFCZs(insemi-enclosedwatersofToloHarbour,MirsBay,andPortShelter)and6FCZsinopenwaters.OurresultsshowthatflushingtimeisthelongestininnerPortShelter(about40daysindryseason),andtheshortestfortheFCZsinopenwaters(lessthanoneweekindryseason).Inaddition,theflushingtimeindryseasoniscommonlylongerthanthatinwetseason:20%~40%formostwell-shelteredFCZs;2.6~4timesfortheothers.Ourresultsindicateapositivecorrelationbetweentheflushingtimeanddistancetoopenboundary,supportingtheviewthattheflushingtimeofaFCZiscloselyrelatedtoitslocation.ThisstudyprovidesasolidbasisformariculturemanagementsuchasthedeterminationofcarryingcapacityofFCZs.

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简介：AccordingtotheshipobservationdataovertheSouthIndianOceanduring1950--1995,taking1°×1°and5°×5°grid,thecharacteristicsandvariationruleofwindareanalyzed.Throughanalyzingthechartofisoplethsofthemonthlyelements,theconclusionthattheseasonalvariationofthewindfieldovertheSouthIndianOceanislessremarkablethanthatintheoceansoftheNorthernHemisphereisgot.Theseasonalvariationofthewindfieldisalsoobviousinthisregion,buttheseasonaldifferenceislittle.Thewindinwinterisstrongerthaninsummer,correspondingly,theaveragewindspeedishigher,andthefrequenciesofgaleofforces≥6and8arealsohigher.Thenorthof10°Sisamonsoonarea;Southeastwindprevailsallovertheyearintherestofthetradewindarea;Westerlywinddominatesinthesouthof40°S.Thispaperprovidesspecificdataofwindfieldandvariationforshipoceantransportation,ocean-goingvisitsandscientificexperiment.

简介：Threekindsofmethods,i.e.,explicit,semi-implicit,andsemi-implicitandsemi-Lagrangianmethod,aretestedinthetime-integrationofshallow-waterequationsonrotatingsphere.Helpfulresultsareavailablefromexperiments,especiallyabouttheaccuracyandefficiencyofdifferentsemi-implicitandsemi-Lagrangianschemes.

简介：在时间域的领域分解和匹配的方法为模仿在波浪进展的轮船的运动被构画出。流动域被想象的控制表面分解成内部、外部的域，并且当短暂格林函数方法在外部域被使用时，Rankine来源方法被用于内部域。二个起始的边界价值问题在控制表面上被匹配。相应数字代码被开发，并且为系列60轮船和S175货柜船在头海进展的增加的群众，波浪激动力量和轮船运动，被介绍并且验证。当数字结果与试验性的数据和另外的引用相比时，一个好协议被获得了。它证明因为面板discretization，现在的方法在数字计算期间在内部领域仅仅是更有效的，并且好数字稳定性被证明与闪光关于轮船避免分叉问题。

简介：FPSOisakindofimportantexploitationplatformusedinoceanoilandgasindustry,whichhastheuniquecharacterofmooringatoutseaforalongtime.Sinceitcannotbeinspectedandmaintainedthoroughlyatdocklikeotherkindsofships,thereliabilityofFPSOhullgirderduringthewholeserviceshouldbefocused.Basedonlatestcorrosiondatabaseandrationalcorrosionmodel,theultimatestrengthofoneFPSOiscalculatedundertheconditionsofslight,moderateandseverecorrosion.Theresultsnotonlyprovidethereliabilityunderdifferentcorrosionconditions,butalsodowellforfurtherinspectionandmaintenanceresearch.Theresultsprovidenecessaryfoundationfordecidinginspectionintervalsandmaintenancemeasures,whichhaspracticalsensetoimprovethegeneralsafetylevelofoceanengineering.

简介：TheJiaozhouBayischaracterizedbyheavyeutrophicationthatisassociatedwithintensiveanthropogenicactivities.FourcoresedimentsfromtheJiaozhouBayareanalyzedusingbulktechnologies,includingsedimentarytotalorganiccarbon(TOC),totalnitrogen(TN),thestablecarbon(δ~(13)C)andnitrogen(δ~(15)N)isotopiccompositiontoobtainthecomprehensiveunderstandingofthesourceandcompositionofsedimentaryorganicmatterandfurthershedlightontheenvironmentalchangesoftheJiaozhouBayonacentennialtimescale.ResultssuggestthattheTOCandTNconcentrationsincreaseintheuppercore,havingindicatedaprobableeutrophicationprocesssincethe1920sintheinnerbayandthe2000sinthebaymouth.TheTOCandTNconcentrationsoutsidethebayhavealsochangedsince1916owingtothevariationofterrigenousinput.ConsideringTOC/TNratio,δ~(13)Candδ~(15)N,itcanbeconcludedthereisamixtureofterrigenousandmarineorganicmattersourcesinthestudyarea.Asimpletwoend-member(terrigenousandmarine)mixingmodelusingδ~(13)Cindicatsthat45%–79%ofTOCintheJiaozhouBayisfromthemarinesource.TheenvironmentalchangesoftheJiaozhouBayarerecordedbygeochemicalproxies,whichareinfluencedbytheintensiveanthropogenicactivities(e.g.,extensiveuseoffertilizers,anddischargeofsewage)andclimatechanges(e.g.,rainfall).

简介：two-time-level，三维的数字海洋发行量模型(命名MASNUM)与一个二水平的、单个步的Eulerian提交向后时差计划被建立。大规模海洋的运动的一个数学模型基于协调的地面追随者，Boussinesq，海洋动力学的平均Reynolds的原始方程。一个简单却很实际的Eulerian提交向后方法被采用为barotropic和baroclinic模式作为时差方法代替大多数比较喜欢的跳蛙游戏计划。提交向后方法具有精确性的秒顺序，由每时间步要求一仅仅功能评估计算地有效，并且没有在三水平的计划固有的计算模式。这个方法比跳蛙游戏计划优异因为稳定性的最大的时间步骤这样象在蹒跚的网孔的跳蛙游戏计划的一样两次大计算效率能被加倍。一个空间变光滑方法被介绍在数字集成控制非线性的不稳定性。模仿赤道的Rossbysoliton的繁殖的一个理想的数字实验被执行测试振幅和这个新模型的阶段错误。这个发行量模型的表演进一步被验证与一地区性(西北太平洋)并且一伪全球(有排除的北极海洋的全球海洋模拟)模拟实验。这二个数字实验与观察显示出相当好的同意。在这二个实验的稳定性的最大的时间步也在采用跳蛙游戏计划的这个模型和那个模型之间被调查并且比较。

简介：Atime-domainmethodisappliedtosimulatenonlinearwavediffractionaroundasurfacepiercing3-Darbitrarybody.ThemethodinvolvestheapplicationofTaylorseriesexpansionsandtheuseofperturbationproceduretoestablishthecorrespondingboundaryvalueproblemswithrespecttoatime-independentfluiddomain.AboundaryelementmethodbasedonB-splineexpansionisusedtocalculatethewavefieldateachtimestep,andthefreesurfaceboundaryconditionissatisfiedtothesecondorderofwavesteepnessbyanumericalintegrationintime.Anartificialdampinglayerisadoptedonthefreesurfacefortheremovalofwavereflectionfromtheouterboundary.Asanillustration,themethodisusedtocomputethesecond-orderwaveforcesandrun-uponasurface-piercingcircularcylinder.Thepresentmethodisfoundtobeaccurate,computationallyefficient,andnumericallystable.

简介：Thecoupledhull,mooringandriseranalysistechniquesintimedomainarewidelyrecognizedastheuniqueapproachtopredicttheaccurateglobalmotions.However,thesecomplexissueshavenotbeenperfectlysolvedduetoalargenumberofnonlinearfactors,e.g.forcesnonlinearity,mooringnonlinearity,motionnonlinearityandsoon.Thispaperinvestigatesthecoupledeffectsthroughthenumericaluncoupledmodel,mooringcoupledmodelandfullycoupledmodelaccountingmooringandrisersbasedonanoveldeepdraftmulti-sparwhichisespeciallydesignedfordeepwaterin2009.Thenumericalstatic-offset,free-decay,wind-actiontestsareexecuted,andfinallythreehourssimulationsareconductedunder100-yearreturnperiodofGOMconditionsinvolvingwave,windandcurrentactions.Thedampingcontributions,responsecharacteristicsandmooringlinetensionsareemphaticallystudied.

简介：Afullycoupled6-degree-of-freedomnonlineardynamicmodelispresentedtoanalyzethedynamicresponseofasemi-submersibleplatformwhichisequippedwiththedynamicpositioning(DP)system.Inthecontrolforcedesign,adynamicmodelofreferencelineardriftfrequencyinthehorizontalplaneisintroduced.Thedynamicsurfacecontrol(DSC)isusedtodesignacontrolstrategyfortheDP.Comparedwiththetraditionalback-steppingmethods,thedynamicsurfacecontrolcombinedwithradialbasisfunction(RBF)neuralnetworks(NNs)canavoiddifferentiatingintermediatevariablesrepeatedlyineverydesignstepduetotheintroductionofafirstorderfilter.LowfrequencymotionsobtainedfromtotalmotionsbyalowpassfilterarechosentobetheinputsfortheRBFNNswhichareusedtoapproximatethelowfrequencywaveforce.Consideringthepropellers’wearandtear,theeffectoffilteringfrequenciesforthecontrolforceisdiscussed.Basedonpowerconsumptionsandpositioningrequirements,theNNcentersaredetermined.Moreover,theRBFNNsusedtoapproximatethetotalwaveforcearebuilttomonitorthedisturbances.WiththeDPassistance,theresultsoffullycoupleddynamicresponsesimulationsaregiventoillustratetheeffectivenessoftheproposedcontrolstrategy.

简介：TheEastChinaSea(ECS)isariver-dominatedepicontinentalsea,linkingtheAsiancontinenttothenorthwesternPacificviathelargeriversoriginatingfromTibetanPlateau.TherelevanthugeinfluxofriverinedetritushasdevelopeduniquesedimentarysystemsintheECSduringtheQuaternary,offeringidealterrestrialarchivesforreconstructingQuaternarypaleoenvironmentalchangesandstudyingland-seainteractions.Overall,twocharacteristicriversystemsdominatethesedimentarysystemsandsedimentsourcetosinktransportpatternsintheECS,representedbytheChangjiang(YangtzeRiver)andHuanghe(YellowRiver)forthelargeriversystemandTaiwanriversforthesmallriversystem.Giventhis,thesedimentsderivedfrombothriversystemsbeardistinctfeaturesintermsofparentrocklithology,provenanceweatheringandsedimenttransport.Previousstudiesmostlyfocusoneitherthe‘source’discriminationorthe‘sink’recordsofthesedimentarysystemintheECS,whilethesourcetosinkprocesslinkingthelandandsea,inparticularitstimescale,hasbeenpoorlyunderstood.Hereweintroduceanewly-developeddatingtechnique,the‘comminutionage’method,whichoffersaquantitativeconstraintonthetimescaleofsedimenttransferfromitsultimatesourcetothefinaldepositionalsink.Thisnovelmethodisofgreatsignificanceforimprovingourunderstandingontheearthsurfaceprocessesincludingtectonic-climatedrivenweathering,andsedimentrecyclinginrelationtolandscapeevolutionandmarineenvironmentalchanges.TheapplicationofcomminutionagemethodintheECSwillprovideimportantconstraintsonsedimentsource-to-sinkprocessandmoreevidencesfortheconstructionoflateQuaternarypaleoenvironmentalchangesundertheseuniquesedimentarysystems.更多还原