简介:Forstudyingthedynamicperformanceofsubseaumbilicalcablelayingsystemandachievingthegoalofcabletensionandlayingspeedcontrol,therigidfiniteelementmethodisusedtodiscreteandtransformthesystemintoarigid-flexiblecouplingmulti-bodysystemwhichconsistsofrigidelementsandspring-dampingelements.ThemathematicalmodelofsubseaumbilicalcablelayingsystemkinematicchainispresentedwiththesecondorderLagrangeequationinthejointcoordinatesystem,anddynamicmodelingandsimulationisperformedwithADAMS.Thedynamicanalysisisconductedassumingthefollowingthreestatuses:ideallaying,practicallayingunderwavedisturbance,andpracticallayingwithtensioncompensation.Resultsshowthatmotiondisturbancesofthelayingbudgeunderseawaves,especiallywithheavingandpitching,willcauserelativelyseriousfluctuationsincabletensionandlayingspeed.Tensioncompensation,i.e.,activebacktensiontorquecontrolcanrestrictcontinuoustensionincreasingordecreasingeffectivelyandrapidly,thusavoidingcablebreachorbuckling.
简介:Smoothedparticlehydrodynamics(SPH)isaLagrangianmeshlessparticlemethod.Itisoneofthebestmethodforsimulatingviolentfreesurfaceflowsinfluidsandsolvinglargefluiddeformations.Dambreakingisatypicalexampleoftheseproblems.ThebasisofSPHwasreviewed,includingsometechniquesforgoverningequationresolution,suchasthesteppingmethodandtheboundaryhandlingmethod.Thennumericalresultsofadambreakingsimulationwerediscussed,andthebenefitsofconceptslikeartificialviscosityandpositioncorrectionwereanalyzedindetail.Whencomparedwithdambreakingsimulatedbythevolumeoffluid(VOF)method,thewaveprofilegeneratedbySPHhadgoodagreement,butthepressurehadonlyreasonableagreement.Improvingpressureresultsisclearlyanimportantnextstepforresearch.
简介:<正>19–24October2014SingaporeCONFERENCETHEMESTheoverallaimoftheICHDConferenceistoprovideaforumforparticipantsfromaroundtheworldtoreview,discussandpresentthelatestdevelopmentsinthebroaddisciplineofhydrodynamicsandfluidmechanics.ThefirstInternationalConferenceonHydrodynamics(ICHD)wasinitiatedin1994inWuxi,China.Sincethen,9moreICHDconferenceswereheldsubsequentlyinHongKong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,ShanghaiandStPetersburg.EvidentlytheICHDconferencehasbecomeanimportanteventamongacademics,
简介:技能层次和知识层次是高职教学的总体目标.高职力学教学对学生智力的开发、观念分析能力的培养、操作技能的锻炼和综合能力的提高有着十分重要的影响,本文对高职力学教师应具有的教学能力进行了探索.
简介:Rigidblockingmassesarelocatedinthetypicalbasestructureofapowercabinbasedontheimpedancemismatchprinciple.Bycombiningtheacoustic-structuralcouplingmethodandstatisticalenergyanalysis,thefull-bandvibrationandsoundradiationreductioneffectofvibrationisolationmasseslocatedinabasestructurewasresearched.Theinfluenceoftheblockingmass’cross-sectionsizeandshapeparametersandthelayoutlocationofthebaseisolationperformancewasdiscussed.Furthermore,theeffectivenessofrigidvibrationisolationdesignofthebasestructurewasvalidated.Theresultsshowthatthemediumandhighfrequencyvibrationandsoundradiationofapowercabinareeffectivelyreducedbyablockingmass.Concerningweightincrementandsectionrequirement,suitablyincreasingtheblockingmasssizeandsectionheightandreducingsectionwidthcanresultinanefficiency-costratio.
简介:Thispaperfocusesontheresearchofasemi-submersibleplatformequippedwithaDP-assistedmooringsystem.BasedontheworkingprinciplesoftheDP-assistedmooringsystemandthemodeloftheplatformmotion,atimedomainsimulationprogramisappliedtoanalyzetheimpact,inthecaseofonelinefailure,ontheplatformmotion,powerconsumptionofthethrustersandthetensionofthemooringlines.Theresultsshowthat,underthe10-yearwinddominant,aonelinefailurewillhavelittleimpactonthetensionofthemooringlines.Whenthefailurelineiswindward,thepowerconsumptionwillincreasegreatlywithaweakenedpositionofaccuracy.Howeverwhenthefailurelineisleeward,thepowerconsumptionwillbereducedwithapartlystrengthenedpositionofaccuracy.
简介:Fishareabletomakegooduseofvortices.Inacomplexflowfield,manyfishcontinuetomaintainbothefficientcruisingandmaneuverability.Traditionalman-madepropulsionsystemsperformpoorlyincomplexflowfields.Withfish-likepropulsionsystems,itisimportanttopaymoreattentiontocomplexflowfields.Inthispaper,theinfluenceofvorticesonthehydrodynamicperformanceof2-Dflapping-foilswasinvestigated.Theflapping-foilheavedandpitchedundertheinfluenceofinflowvorticesgeneratedbyanoscillatingD-sectioncylinder.Anumericalsimulationwasrunbasedthefinitevolumemethod,usingthecomputationalfluiddynamics(CFD)softwareFLUENTwithReynolds-averagedNavier-Stokes(RANS)equationsapplied.Inaddition,dynamicmeshtechnologyandpostprocessingsystemswerealsofullyused.Thecalculationsshowedfourmodesofinteraction.Thehydrodynamicperformanceofflapping-foilswasanalyzedandtheresultscomparedwithexperimentaldata.Thisvalidatedthenumericalsimulation,confirmingthatflapping-foilscanincreaseefficiencybyabsorbingenergyfrominflowvortices.
简介:针对船舶动力系统润滑油水分检测耗时长的问题,根据润滑油导电性随含水率变化的特点,设计出基于电导传感器的润滑油水分在线、实时检测系统,系统通过获得电导传感器测量油水混合液的输出电压计算润滑油的含水率。该仪器主要包括电导传感器与激励源模块、单片机STM32F103C8模块、信号采集模块和液晶显示模块等构成。实验结果表明电导传感器润滑油水分检测系统能够准确、方便、快速地实现检测功能。