学科分类
/ 3
46 个结果
  • 简介:Forstudyingthedynamicperformanceofsubseaumbilicalcablelayingsystemandachievingthegoalofcabletensionandlayingspeedcontrol,therigidfiniteelementmethodisusedtodiscreteandtransformthesystemintoarigid-flexiblecouplingmulti-bodysystemwhichconsistsofrigidelementsandspring-dampingelements.ThemathematicalmodelofsubseaumbilicalcablelayingsystemkinematicchainispresentedwiththesecondorderLagrangeequationinthejointcoordinatesystem,anddynamicmodelingandsimulationisperformedwithADAMS.Thedynamicanalysisisconductedassumingthefollowingthreestatuses:ideallaying,practicallayingunderwavedisturbance,andpracticallayingwithtensioncompensation.Resultsshowthatmotiondisturbancesofthelayingbudgeunderseawaves,especiallywithheavingandpitching,willcauserelativelyseriousfluctuationsincabletensionandlayingspeed.Tensioncompensation,i.e.,activebacktensiontorquecontrolcanrestrictcontinuoustensionincreasingordecreasingeffectivelyandrapidly,thusavoidingcablebreachorbuckling.

  • 标签: subsea UMBILICAL cable LAYING system RIGID
  • 简介:Smoothedparticlehydrodynamics(SPH)isaLagrangianmeshlessparticlemethod.Itisoneofthebestmethodforsimulatingviolentfreesurfaceflowsinfluidsandsolvinglargefluiddeformations.Dambreakingisatypicalexampleoftheseproblems.ThebasisofSPHwasreviewed,includingsometechniquesforgoverningequationresolution,suchasthesteppingmethodandtheboundaryhandlingmethod.Thennumericalresultsofadambreakingsimulationwerediscussed,andthebenefitsofconceptslikeartificialviscosityandpositioncorrectionwereanalyzedindetail.Whencomparedwithdambreakingsimulatedbythevolumeoffluid(VOF)method,thewaveprofilegeneratedbySPHhadgoodagreement,butthepressurehadonlyreasonableagreement.Improvingpressureresultsisclearlyanimportantnextstepforresearch.

  • 标签: MESHLESS method smoothed PARTICLE HYDRODYNAMICS (SPH)
  • 简介:<正>19–24October2014SingaporeCONFERENCETHEMESTheoverallaimoftheICHDConferenceistoprovideaforumforparticipantsfromaroundtheworldtoreview,discussandpresentthelatestdevelopmentsinthebroaddisciplineofhydrodynamicsandfluidmechanics.ThefirstInternationalConferenceonHydrodynamics(ICHD)wasinitiatedin1994inWuxi,China.Sincethen,9moreICHDconferenceswereheldsubsequentlyinHongKong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,ShanghaiandStPetersburg.EvidentlytheICHDconferencehasbecomeanimportanteventamongacademics,

  • 标签: 水动力学 国际 会议
  • 简介:Sloshingphenomenonintheliquidcargocarriershascaughttheattentionofresearchersastheinteractionbetweenthesloshingwavesandstructureisoneofthekeypointanddifficultyinthestudyofsloshing.Inthispaper,wecapturedthefreesurfacewithavolumeoffluid(VOF)methodandthencalculatedthemotionsandresponsesofthestructurebyadoptingtheReynolds-averagedNavier-Stokes(RANS)equationsforthewholefluiddomain.Withtheuseofuserdefinedfunctions(UDF)inFluent,theinteractionbetweenfluidandstructurewasthensimulated.Asareasonablesimplification,theauthorsstudiedtheresponseofasinglecantileverinatankundersloshingloads;Furtherstudyshouldpaymoreattentiontothemechanismsofinteractionbetweensloshingwavesandelasticstructures.

  • 标签: LIQUID SLOSHING FLUENT DEFORMATION NUMERICAL simulation
  • 简介:台湾酝酿建立弹性学制为了确立21世纪台湾的教育政策,在1994年6月召开的全台教育会议上,重点讨论了建立弹性学制的问题,对现行学制要进行“全面检讨,大幅调整”已成为全体代表的共识。台湾现行的学制,即所谓“六三三四”学制(小学6年,初中3年,高中3年,...

  • 标签: 弹性学制 义务教育 台湾 入学方式 学年学分制 完全学分制
  • 简介:Thispaperpresentsananalyticalstudyontheinfluenceofedgerestrainingstiffnessonthetransversevibrationsofrectangularplatestructure.AnimprovedFourierseriesmethodwasemployedtoanalyzethetransversevibrationofplatestructurewithgeneralelasticallyrestrainedboundaryconditions.AlinearcombinationofadoubleFourierseriesandeightauxiliarytermswassoughtastheadmissiblefunctionoftheflexuraldisplacementoftheplate,eachtermbeingacombinationofapolynomialfunctionandasinglecosineseriesexpansion.Theauxiliarytermswereintroducedtoensureandimprovethesmoothnessoftheoriginaldisplacementfunctionanditsderivativesattheboundaries.Severalnumericalexamplesweregiventodemonstratethevalidityandaccuracyofthecurrentsolution.Theinfluencesoftranslationalandrotationalstiffnessonthenaturalfrequenciesandmodeshapesofplatewereanalyzedbynumericalresults.Theresultsshowthatthetranslationalstiffnesshasbiggerinfluenceonthenaturalfrequenciesthantherotationalstiffness.Itisgenerallywellknownthatlittlechangeoftherotationalstiffnesshaslittleinfluenceonthemodeshapesofplate.However,thecurrentworkshowsthataverylittlechangeofrotationalstiffnessvaluemayleadtoalargechangeofthemodeshapesofasquareplatestructure.

  • 标签: VIBRATION PLATE DOUBLE FOURIER series ELASTIC
  • 简介:针对危险化学品泄漏事故不断增多的趋势,分析了危险化学品泄漏事故发生的原因、危害、液体化学品泄漏可能带来的水域污染危害,以及国际液体化学品的特性,并提出了危险化学品泄漏事故的处置措施,以期望为从事化学品运输人员提供借鉴作用.

  • 标签: 液体化学品 泄漏 应对措施
  • 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.

  • 标签: 高职教育、教学能力、职业技能
  • 简介:近年来,随着深海石油工业的发展,立管的涡激振动现象越来越受学者们关注.使用RANS方程求解器,并结合SSTκ-ω湍流模型,对横向和流向自然频率比为1的低质量比弹性支撑圆柱体的两自由度运动进行了数值模拟,计算雷诺数范围为5300至32000.采用四阶Runge—Kutta方法求解柱体的振动方程.并结合近期物理实验结果对升力系数、阻力系数、位移和尾涡模式进行了详细比较和讨论.较好地再现了试验观察到的锁定、迟滞、差拍等现象。

  • 标签: 涡激振动 低质量比 流向与横向运动 两自由度 涡发放模型 CFD
  • 简介:Theproblemofwaterwavescatteringbyathinverticalelasticplatesubmergedinuniformfinitedepthwaterisinvestigatedhere.TheboundaryconditionontheelasticplateisderivedfromtheBernoulli-Eulerequationofmotionsatisfiedbytheplate.UsingtheGreen’sfunctiontechnique,fromthisboundarycondition,thenormalvelocityoftheplateisexpressedintermsofthedifferencebetweenthevelocitypotentials(unknown)acrosstheplate.Thetwoendsoftheplateareeitherclampedorfree.Thereflectionandtransmissioncoefficientsareobtainedintermsoftheintegrals’involvingcombinationsoftheunknownvelocitypotentialonthetwosidesoftheplate,whichsatisfythreesimultaneousintegralequationsandaresolvednumerically.Thesecoefficientsarecomputednumericallyforvariousvaluesofdifferentparametersanddepictedgraphicallyagainstthewavenumberinanumberoffigures.

  • 标签: thin vertical elastic plate uniform finite
  • 简介:刚刚召开的全国两会,部署2017年国企改革工作时明确宣示要以提高核心竞争力和资源配置效率为目标。提高国企竞争力是国企改革的重要目标,而且要聚焦于“核心”,而“资源配置效率”是市场经济个性用词,是为实现核心竞争力的手段。

  • 标签: 国企改革 资源配置效率 核心竞争力 市场经济 工作时
  • 简介:《经1978年议定书修订的1973年国际防止船舶造成污染公约》(73/78防污公约)附则Ⅱ修正案及经修订的《国际散装运输危险化学品船舶构造与设备规则》(IBC规则)已于2007年1月1日生效。按照《73/78防污公约》附则Ⅱ第6.3条规定,未分类散装液体物质应根据(73/78防污公约》附则Ⅱ第6.1条进行分类,并在所有相关国家之间达成一致,否则不得装运。

  • 标签: 散装运输 液体物质 中国海事局 分类 船舶 73/78防污公约
  • 简介:通过讨论动力定位系统(DPS)的功能特性,以及对DP操作员(DPO)的技能要求,分析国外培训机构在开展DPO适任培训的可借鉴之处,探讨动力定位模拟器在DP操作员适任培训中的应用.

  • 标签: 动力定位 海洋工程 航海模拟器
  • 简介:文章通过对技术技能型人才力学知识的需求现状分析,提出了基于"工程力学"课程创新高职人才培养模式的具体措施,对提升高职人才培养质量,具有一定的参考意义。

  • 标签: 高职教育 工程力学 人才培养 创新
  • 简介:出于运营经济性与安全性的目的,中小型LNG动力船舶供气系统的储罐一般选用C型储罐.对于储罐的设计,首先是要根据内压储罐的设计要求进行设计计算,然后,针对所设计的壁厚等参数依据相应规范进行适当的校核,以保证强度的要求.

  • 标签: 小型LNG动力船 C型储罐 有效容积 强度校核
  • 简介:Thispaperfocusesontheresearchofasemi-submersibleplatformequippedwithaDP-assistedmooringsystem.BasedontheworkingprinciplesoftheDP-assistedmooringsystemandthemodeloftheplatformmotion,atimedomainsimulationprogramisappliedtoanalyzetheimpact,inthecaseofonelinefailure,ontheplatformmotion,powerconsumptionofthethrustersandthetensionofthemooringlines.Theresultsshowthat,underthe10-yearwinddominant,aonelinefailurewillhavelittleimpactonthetensionofthemooringlines.Whenthefailurelineiswindward,thepowerconsumptionwillincreasegreatlywithaweakenedpositionofaccuracy.Howeverwhenthefailurelineisleeward,thepowerconsumptionwillbereducedwithapartlystrengthenedpositionofaccuracy.

  • 标签: DP-assisted MOORING system time DOMAIN simulation
  • 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.

  • 标签: flapping-foil VORTEX numerical simulation HYDRODYNAMIC performance
  • 简介:设计了一种新型的管道水流余压能利用方案,进行了理论分析和计算,开发了一种新型的小型的余压能发电装置,并进行了性能试验测试;理论分析和计算结果表明:余压能发电装置最大输入功率随着流量的增加,先增加后减小,当流量较大时,末端数少的余压能发电装置最大输入功率较大,末端数多的余压能发电装置最大输入功率较小.试验测试结果表明:小型余压能发电装置平均输出电压测试为34.5V,平均功率为12.6W,可驱动LED灯单元及小型风扇.

  • 标签: 余压能 功率 流量
  • 简介:在概述轮机类专业“工程力学”教学现状的基础上,分析“工程力学”教学存在的问题,提出对轮机类专业实行“工程力学”模块化教学的构想,结合教学实际探讨“工程力学”模块化教学的实行方案以及需要注意的问题。

  • 标签: 工程力学 模块化教学 轮机类专业