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7 个结果
  • 简介:BasedonGreen’stheorem,atimedomainnumericalmodelwasconstructedtosimulatewavemakingphenomenoncausedbyamovingship.Inthisarticle,theRankinesourcesanddipoleswereplacedonboundarysurfaces(i.e.,theshipsurfaceandfreesurface),andatime-steppingschemewasemployed.Itsuniquecharacteristicisthatsteadystatecanberealizedfrominitialvaluebyemployingthetime-steppingschemeandunsteadyfreesurfaceconditions.Intimedomain,iftheresultsofunsteadyflowproblemtendtodatastabilizationaftermanytimestepsofcomputation,theycouldberegardedasthedataofsteadyones.Thismodelcouldbeemployedtosteadyorunsteadyproblems.Theoreticalreasoningandcomputationalprocessofthismethodwasdescribedindetail.Thelinearandnonlinearboundaryconditionsonbodysurfacewerestudied,andtherelativemeanstorealizetheseboundaryconditionsiniterativecomputationwerealsodiscussed.SomeproperparametersaboutthemodeloftheWigleyhullweredeterminedbymanynumericaltests,andtheirinfluencesonwavemakingresistanceandwavepatternwerediscussed.Accordingtothecomparisonbetweennumericalresultsanddataavailableinrelativereferences,themethodusedinthisworkisproventobeareliablemethodintimedomain.Andthelatticereorganizationineverytimestepcomputationisafeasiblenumericalapproach.

  • 标签: 兰金 偶极子 格子 波形
  • 简介:Time-domainanalysisisusedtopredictwaveloadingandmotionresponsesforashiptravellingataconstantspeedinregularobliquewaves.Thecombineddiffractionandradiationperturbations,causedbythesteadyforwardspeedoftheshipandhermotions,areconsideredasadistributionofnormalvelocitiesonthewettedhullsurface.Theship-hullboundaryconditionisexactlyfulfilledbyexpressingthefluidnormalvelocitiesasafiniteseriesintermsofthebodygeometryandtheincidentwavepotential.Asfarastheauthorsareaware,nosimilarworkispublishedtodate.ThenewtheoryisappliedtopredictforcesandmotionsatforwardspeedforaWigleyship-hullinheadwavesandacatamaran-ferryinobliquewaves.PredictionsarecomparedwithpublishedtheoreticalandexperimentalresultsfortheWigleyship-hull,andthecomparisonisgood.Forthecatamaran,aself-propelledmodelisbuiltandtestedinthelargetowingtankandseakeepingbasinoftheChinaShipScientificResearchCentre,Wuxi

  • 标签: TIME-DOMAIN SHIP motion.
  • 简介:Atime-domainKelvinsourcehigh-orderpanelmethodbasedonNURBSisdevelopedandappliedtosolvetheunsteadywave-makingproblems.Numericalresultsofinstantwaveresistanceandfreesurfaceelevationarepresentedandcomparedwiththeavailabyresultsbyotherauthors,forsubmergedspheroidandspherebeneaththefreesurfaceandforsurfaceshipofWigleymodelsmovingwithunsteadyspeed.Theagreementissatisfying.

  • 标签: 时间因素 数值仿真 不稳定船舶波动 NURBS 高阶镶嵌法
  • 简介:Thesimulationsofnonlinearsloshinginbothtwo-dimensionalandthree-dimensionalliquidtankswithporositygirderarecarriedoutintimedomainbyusingtheMulti-domainBoundaryElementMethod(MBEM).Thecomparisonofthepresentresultsandthereferencesisconductedandshowstheyagreewellwitheachother.Thethree-dimensionaleffectandtheinfluenceofthewidthofliquidtankandtheheightandporosityofthegirderonthenaturalperiodofthemodelarealsodiscussed.

  • 标签: 非线性晃动 边界元法 孔隙度 模拟 坦克
  • 简介:A3-Dtimedomainmethodisdevelopedtoinvestigatethegapinfluenceonthewaveforcesfor3-Dmultiplefloatingstructures.Specialhydrodynamicresonanceduetosmallgapsbetweenmultiplefloatingstructuresonwaveforcesisexamined.Strongandcomplicatehydrodynamicinteractionsbetweenthefloatingbodiesareobservedandthenumericalcomputationshaveprovedtheexistenceofthesharppeakforceresponseoneachfloatingbodyatsomespecialresonantwavenumbers.Bycomparisonwiththeresultsfromthefrequencydomaintechnique,theresultsobtainedfromthetimedomainmethodrevealthesimilarresonantphenomenaandhydrodynamicinteraction.TheresonantwavenumbersarealsoprovedaroundkL=nπ(n=1,2,…,∞)withacorrespondingfrequencyshift.Thestronghydrodynamicinteractionfeatureispracticallysignificantforthedesignofmodulestructuresandthelinks(connection)inwholethefloatingbodysystem.

  • 标签: 时间域 共振技术 流体动力学 浮动体
  • 简介:Makingfulluseoffunctionalvariationswithvariabledomainforhandlingboththefreesurfaceandunknownpartofthedamwall,afamilyofvariationalprinciples(VPs)forthehybrid(direct-inverse)problemoffreesurfacespillwayflowundergravityisformulatedintermsofthepotentialfunctionΦ.Thistheoryoffersnewrationalandversatilewaysfordamde-signandasoundtheoreticalbasisfornumericalsolution,e.g.bythefiniteelementmethod(FEM).

  • 标签: dam design finite element method FREE-SURFACE