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简介：TNT的数字模拟在水下爆炸与AUTODYN被执行软件。模拟结果上的人工的粘性和网孔密度的影响被讨论。在炸药的爆炸波浪和水里的冲击波在爆炸的早时间期间是高频率波浪。好网孔(不到1，公里)在炸药和水附近、小的线性粘性系数和二次的粘性系数(0.02和0.1分别地，缺省值的1/10)在数字模拟模型被需要。根据这些规则，数字计算压力侧面能匹配很好，那些由Zamyshlyayev实验公式计算了。不同山峰压力将被涂离开，在上游的相对错误将下游地被堆积使下游的山峰压力更低。

简介：Ifthefrequencyoftheincidentsoundwavecoincideswithoneoftheeigenfrequenciesoftheunderwaterelasticcylinder,thecorre-spondingeigenvibrationwillbeexcitedbyincidentsoundwaveandstronglyreradiatesoundwavetowardssurrondingwater.Ithasbeenre-vealedbypreviousinvestigationsthattheamplitudeofbackscatteringsoundappearstobeminimumattheeigenfrequenciesoftheunderwatermetalliccylindersbecauseofthedestructiveinterferencebetweenreradiatedwaveoftheeigenvibrationandthegeometricalreflectedwavefromsurfaceofthecylinders.Inthispaper,anewphenomenonhasbeenrevealed.Theamplitudeofbackscatteringsoundappearstobemaximumattheeigenfrequenciesofacylindermadefromnonmetallicmaterialinwhichthevelocityofelastictransversewaveislessthanthesoundvelocityinwater.

简介：Timereversalisappliedtotheunderwaterspreadingspectrumcodingcommunication.Onthebaseofanalyzingthefocusingcharacteristicsofthetimereversalinunderwaterwaveguide,thetimereversalisstudiedtoovercomethewavedistortionoftheencodedsignalcausedbythemulti-patheffect.TheexperimentresearchforunderwatercodingcommunicationiscarriedoutinalabwatertankandthecorrespondingtheoreticalanalysisisalsoconductedbyBinaryPhaseShiftKeying(BPSK)encodingandBarkercodewith7chipsforthespreadingspectrumsignal.Theresultsshowthatthetimereversalcanimprovethefocusinggainandincreasetheratiooftheprincipaltothesecondlobeofthecodingsignal,andcandecreasethebiterrorrateandincreasethecommunicationdistance.

简介：-Thisarticlebriefshowtoimprovetheholdingpowerofadrillingvessel’sanchorandtoremovethoseunreasonablestructuresbysuchatechnology-underwater-explosiontechnology.Thearticlegivesdetailsofthestructure,characteristicsandapplicationsofarocket-launchedanchor;aswellastheprinciple,properties,applicationsofdirectionalexplosioncutting.

简介：Inthispaper,maximum-likelihood(ML)anditsrelaxationalgorithm,whichareusedtoidentifythemathematicsmodelofanunderwatervehicle(UV),arcdiscussed.Withthetrialdataofzigzagtests,thehydrodynamicderivativesoftheUVwereestimated,andtherelaxationalgorithmisconfirmedtohavebetterastringencyfromthecontrastbetweenthetwomethods.Thenasimulationenvironmentbasedontheseparametersisestablishedtoverifythevalidityandeffectofthesemeth-ods.Theresultshowsthemodeliscredibleandthemethodsareveryusefulfortheresearchofmaneuverabilityandadaptivecontrolofunderwatervehicles.

简介：Anewmethodofcodinganddecodinginthesystemofunderwaterimagetransmissionisintroduced,includingtherapiddigitalfrequencysynthesizerinmultiplefrequencyshiftkeying,imagedatagenerator,imagegrayscaledecoderwithintelligentfuzzyalgorithm,imagerestorationanddisplayonmicrocomputer.

简介：Inthispaper,theunderwatervehicle,slingandthemothershipareconsideredasasinglede-greeoffreedomsystemconnectedbyaspring.Throughtheanalysisofthissystem,aphysicalmodelises-tablished,whichdescribesthemotionofthevehiclecausedbytheshipmotionandwavemotion.Furthermore,amathematicalmodelbasedonthisphysicalmodelisobtained,andanumericalsolutionprogramismade.Asanexample,apracticallaunchandrecoverysystemforanunderwaterrobotiscalcu-latedbyuseoftheprogram.andthemotiontrackoftherobotisobtained.

简介：Theresearchonunderwatership-hullcleaningrobotwasconductedonthepurposeofrealizingtheautomationofcleaningunderwatershiphullsothatservicelifeofshipwillbeprolongedandshipspeedwillraised.Moreover,fuelconsumptionandtheworkintensityofdiverswillbereduced.Inthispaper,thecurrentsituationandthelatesttechnologyinChinaandabroadwereanalyzed;meanwhile,thetypicalcharacteristicsoftheunderwatercleaningrobotwereintroduced.Accordingtotheworkprincipleoftheunderwatercleaningrobot,theemphasiswasputontheanalysisandstudyofpermanent-magneticabsorption,magneticwheel,airproofandanticorrosion,underwatercleaningequipmentandcontrolsystem.Therobotiseasyinrotationandsimpleincontrol.

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简介：Underwatergliders,whichglidethroughwatercolumnsbyuseofapairofwings,areefficientlong-distance,long-durationmarineenvironmentobservatoryplatforms.TheSea-Wingunderwaterglider,developedbytheShenyangInstituteofAutomation,CAS,isdesignedfortheapplicationofdeep-seaenvironmentvariablesobservation.Thesystemcomponents,themechanicaldesign,andthecontrolsystemdesignoftheSea-Wingunderwaterglideraredescribedinthispaper.Thepitchandrolladjustingmodelsarederivedbasedonthemechanicaldesign,andtheadjustingcapabilitiesforthepitchandrollareanalyzedaccordingtothemodels.Fieldexperimentshavebeencarriedoutforvalidatingtheglidingmotionandtheabilityofmeasuringoceanenvironmentvariables.Experimentalresultsofthemotionperformancesofthegliderarepresented.

简介：Thepressurereflectedfromabi-laminatedpiezoelectricplatehasbeendeterminedusingtheThomson-Haskellmatrixmethod.Theplateiscomposedofapiezoelectriclayerwithgroundedvacuumandanelasticlayerincontactwiththefluid.Anincidentplanewaveinthefluidmediumstrikestheplateatdif-ferentangles.Therequiredelectricpotentialacrossthepiezoelectriclayertocancelthereflectionfromthefluid/elasticboundaryhasbeendeterminedforthepiezoelectricmaterialPZT-5atvariousthicknessparame-lersandincidentfrequencies.

简介：Anovelefficienttrackinitiationmethodisproposedfortheharshunderwatertargettrackingenvironment(heavyclutterandlargemeasurementerrors):tracksplitting,evaluating,pruningandmergingmethod(TSEPM).Trackinitiationdemandsthatthemethodshoulddeterminetheexistenceandinitialstateofatargetquicklyandcorrectly.Heavyclutterandlargemeasurementerrorscertainlyposeadditionaldifficultiesandchallenges,whichdeteriorateandcomplicatethetrackinitiationintheharshunderwatertargettrackingenvironment.Therearethreeprimaryshortcomingsforthecurrenttrackinitiationmethodstoinitializeatarget:(a)theycannoteliminatetheturbulencesofcluttereffectively;(b)theremaybeahighfalsealarmprobabilityandlowdetectionprobabilityofatrack;(c)theycannotestimatetheinitialstateforanewconfirmedtrackcorrectly.Basedonthemultiplehypothesestrackingprincipleandmodifiedlogic-basedtrackinitiationmethod,inordertoincreasethedetectionprobabilityofatrack,tracksplittingcreatesalargenumberoftrackswhichincludethetruetrackoriginatedfromthetarget.Andinordertodecreasethefalsealarmprobability,basedontheevaluationmechanism,trackpruningandtrackmergingareproposedtoreducethefalsetracks.TSEPMmethodcandealwiththetrackinitiationproblemsderivedfromheavyclutterandlargemeasurementerrors,determinethetarget’sexistenceandestimateitsinitialstatewiththeleastsquaresmethod.What'smore,ourmethodisfullyautomaticanddoesnotrequireanykindmanualinputforinitializingandtuninganyparameter.Simulationresultsindicatethatournewmethodimprovessignificantlytheperformanceofthetrackinitiationintheharshunderwatertargettrackingenvironment.

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简介：Predictionandvalidationoflow-frequencylinespectrumnoisefromshippropellerundernon-cavitatingconditionispresented.Theflowfieldisanalyzedwithpotential-basedpanelmethod,whichrequiresthehydrodynamicforcestobeintegratedovertheactualbladesurface,ratherthanoverthemean-chordsurface.ThenthepressuredataisusedastheinputforFfowcsWilliams-Hawkingsformulationtopredictthefarfieldacoustics.Atthesametime,propellerunsteadyforceismeasuredinhull-behindconditioninChinaLargeCavitationChannel(CLCC).Linespectrumnoiseofthe1stbladepassagefrequency(BPF)ofafive-bladedpropelleroperatinginanon-uniformflowfieldisgotaccordingtothecalculatedandmeasuredunsteadyforces,inwhichgoodagreementisobtained,andthe1stBPFnoisedifferenceiswithin3.0dB.Theinvestigationrevealsthatpredictionprecisionofthepropeller’s1stBPFunsteadyforcewithpanelmethodhavereachedengineeringpracticaldegree,providingsignificantparametersforpredictionofpropellerlinespectrumnoise.

简介：Anewpiezoelectricpumpcanpumpliquideitherforwardorbackwardandadjusttheflowrate.Thusanobjectcanbedrivenforwardorbackwardatdifferentspeeds.Thedriverofthepump,acircularpiezoelectricplate,ismodelledbyFiniteElementMethod(FEM)inANSYSanditsperformanceissimulatedandanalyzed.Thepumpgivesthebestperformancewhenthedrivingsignalsoftheinletandoutletvalveshaveabiggerdutycycleandtheplatehasahighervoltageapplied.

简介：在水下滑翔机是最近的创新类型自治在水下车辆(AUV)在海洋探索和观察使用了。他们调整快活潜水并且回到海洋表面。在高度的变化期间，他们使用力量由他们的翅膀开发了向前移动的水动力学。他们的班机被改变他们的重心和他们的快活的位置调整他们的修剪和脚跟角度控制。为更好的飞行控制，水动力学行为的理解和飞行力学在水下滑翔机是必要的。A6-DOF运动模拟器被结合为这个目的一个不稳定的潜在的流动模型。在一些特定的盒子中，数字学习证明一种不恰当的stabilizer尺寸能引起相反驾驶的行为。模拟器能被用来改进自动飞行控制。它能也被用于设备的水动力学设计优化。

简介：Theunderwateracousticimagetransmissionsystembasedonthehigh-speedDSPdeviceTMS320C549hasbeenstudied.WeuseGoertzelalgorithmforsourcedecodingandMFSKformodulation.Turbocodeisusedforchannelcodinganddecoding.Thepurposeistoimplementunderwatervideoimagedatatransmission.

简介：为识别的目的SWATH(小Waterplane区域双胞胎的赫尔)严厉有效地并且完善SWATH轮船鈥檚表演的察觉技术，这份报纸基于规模论述新奇双向图象登记策略和mosaicing技术不变的特征变换(筛)算法。建议方法能帮助我们观察与为分析SWATH的控制鳍的性能的一个大视觉角度严厉。筛是规模，旋转和照明的最有效的本地特征之一不变。然而，在这个算法有一些假火柴率。以在水下机器视觉，仅仅由获得一个精确火柴率罐头，我们发现一在水下机器人很快并且识别目标的地点。第一，因此，火柴比率原则的选择在这份报纸被提出；第二，双向登记算法的一些优点被分析单向性的匹配方法的特征结束。最后，一自动在水下图象拼接方法根据图象的固定尺寸，然后边被建议鈥檚重叠节被主要部件分析算法合并。试验性的结果完成更好的登记和光滑的mosaicing效果，证明建议方法是有效的。