简介：ＳＨＩＰＨＹＤＲＯＤＹＮＡＭＩＣＳＢＡＳＩＣＲＥＳＥＡＲＣＨＩＮＴＨＥＵＮＩＴＥＤＳＴＡＴＥＳ￥ＥｄｗｉｎＰ．Ｒｏｏｄ（ＭｅｃｈａｎｉｃｓａｎｄＥｎｇｅｒｇｙＣｏｎｖｅｒｓｉｏｎ（３３３），ＯｆｆｉｃｅｏｆＮａｖａｌＲｅｓｅａｒｃｈＡｒｌｉｎｇｔｏｎ...

简介：Inthisarticle,anewacoustictesttechniqueusingtowedmodelwasintroducedtostudyflownoisecausedbyasurfaceship.Theprojectofmodeltestwasbeproperlydesignedforacousticsignalcollectingandwiththehelpofappropriatedataprocessingmethoddifferentkindsofacousticsourcescouldbesuccessfullyidentified.Alotofworkaboutfuidnoisecouldbecarriedonwiththetowedmodel,andthenoisecorrespondingtolowfrequencywhichisespeciallyinterestedforitslongdistanceradiatingwithsmallattenuationcouldalsobestudiedinthisway.

简介：Hydrodynamicoptimizationofthehullformscanberealizedthroughtheimplementationandintegrationofcomputationaltoolsthatconsistofahydrodynamicmodule,ahullsurfacerepresentationandmodificationmodule,andanoptimizationmodule.Inthepresentpaper,anewbulbousbowgenerationandmodificationtechniquehasbeendevelopedandintegratedintothehullsurfacerepresentationandmodificationmodule.Aradialbasisfunctionbasedsurrogatemodelisdevelopedtoapproximatetheobjectivefunctionsandreducethecomputingcost.Amulti-objectiveartificialbeecolonyoptimizationalgorithmisimplementedandintegratedintotheoptimizationmodule.Toillustratetheintegratedhydrodynamicoptimizationtools,acargoshipisoptimizedforreduceddrag.Theoptimalhullformsobtainedarethenvalidatedcomputationallyandexperimentally.Validationresultsshowthatthepresenttoolscanbeusedefficientlyandeffectivelyinthesimulationbaseddesignofthehullformsforreduceddrag.

简介：Atheoreticalmodelwasusedtoinvestigatetheinfluencesofenvironmentalandtopographicparametersontheatmosphericthree-layerinternalshipwaves.TheresultsshowthatboththewavelengthandthewedgeangledecreasewithanincreaseintheScorerparameter,andtherateofchangesinthewavelengthandwedgeanglearealsoalike.Theresultsalsoshowthatthewedgeangledecreaseswithanincreaseinthewidthofmountain,butthewavelengthvarieslittlewithit.Itissuggestedthatthewedgeangleisdeterminedbytheratioofthewavelengthtothescaleofthemountain.Besides,numericalsensitivityexperimentswereperformedtotesttheformernumericalexperiments.Thesimulatedresultsareconsistentwiththeanalyticalresults.

简介：Anefficientmulti-blockincompressibleviscousflowsolverbasedonsolvingtheReynolds-AveragedNavier-Stokes(RANS)equationsnumericallyhasbeendevelopedthatcanbeappliedtosimulationofavarietyofshipmaneuveringrelatedflowsandcalculationofhydrodynamicforces.Validationandverificationofthesolutionprocedurewerecarriedoutonseveralmodelproblemswithgoodagreementtoexperimentalandnumericalresults.

简介：BasedonthedoubleFourierintegralrepresentationforsteadyviscousshipwaves,whichinvolvesagenericamplitudefunctionandacomplexdispersionrelation,thephasefunctionforthree-dimensionalshipwavesinthefarfieldwasasymptoticallyderivedbymeansoftheLighthilltwo-stageschemecombiningtheCauchyresiduetheoremandthemethodofsteepestdescents,andtheeffectofviscosityonwavelengthswasnumericallyinvestigatedwiththeNewtoniterationmethod.Itisfoundthatthetransverseanddivergingwavesareelongatedduetothepresenceofviscosityandthelatterismoreheavilyaffectedandthatthephasedifferencesbetweentheviscoustransverseanddivergingwavesarelargerthanthoseofthecorrespondinginviscidwaves.

简介：Theshiphullsurfaceoptimizationbasedonthewaveresistanceisanimportantissueintheshipengineeringindustry.Thewaveletmethodmayprovideaconvenienttoolforthesurfacehulloptimization.Asapreliminarystudy,weusethewaveletmethodtooptimizethehullsurfacebasedontheMichelwaveresistanceforaWigleymodelinthispaper.Firstly,weexpressthemodel’ssurfacebythewaveletdecompositionexpressionsandobtainareconstructedsurfaceandthenvalidateitsaccuracy.Secondly,werewritetheMichelwaveresistanceformulainthewaveletbases,resultinginasimpleformulacontainingonlytheshiphullsurface’swaveletcoefficients.Thirdly,wetakethesewaveletcoefficientsasoptimizationvariables,andanalyzethemainwaveresistancedistributionintermsofscalesandlocations,toreducethenumberofoptimizationvariables.Finally,weobtaintheoptimalhullsurfaceoftheWigleymodelthroughgeneticalgorithms,reducingthewaveresistancealmostbyahalf.Itisshownthatthewaveletmethodmayprovideanewapproachforthehulloptimization.

简介：(IWSH'2015,26-28August2015,Glasgow,UK)In1999,thefirstInternationalWorkshoponShipHydrodynamicswassuccessfullyheldinWuhan,China.ThenitwasheldinWuhan,Shanghai,Zhenjiang,Harbin,Seoulinsubsequenteverytwoyears.TheseConferenceshaddrawnavarietyofinternationaldelegatesincludingscientists,engineersandresearcherswithacommoninterestinshiphydrodynamics.Theyprovidedaforumtopromotescientific

简介：Inthispaper,numericalpredictionofshipmotionresponsesinlong-crestirregularwavesbytheURANS-VOFmethodispresented.Awhitenoisespectrumisappliedtogeneratetheincomingwavestoevaluatethemotionresponses.Theprocedurecanreplaceadecadeofsimulationsinregularwavewithonesingleruntoobtainacompletecurveoflinearmotionresponse,considerablyreducingcomputationtime.Acorrectionprocedureisemployedtoadjustthewavegenerationsignalbasedonthewavespectrumandachievesfairlybetterresultsinthewavetank.Threeshipmodelswithfivewaveconditionsareintroducedtovalidatethemethod.Thecomputationsinthispaperarecompletedbyusingthesolvernaoe-FOAM-SJTU,asolverdevelopedforshipandoceanengineeringbasedontheopensourcecodeOpenFOAM.Thecomputationalmotionresponsesbytheirregularwaveprocedurearecomparedwiththeresultsbyregularwave,experimentsandstriptheory.Transferfunctionsbyirregularwavecloselyagreewiththedataobtainedintheregularwaves,showingnegligibledifference.Thecomparisonbetweencomputationalresultsandexperimentsalsoshowgoodagreements.TheresultsbetterpredictedbyCFDmethodthanstriptheoriesindicatethatthismethodcancompensatefortheinaccuracyofthestriptheories.Theresultsconfirmthattheirregularwaveprocedureisapromisingmethodfortheaccuratepredictionofmotionresponseswithlessaccuracylossandhigherefficiencycomparedwiththeregularwaveprocedure.

简介：Time-domainanalysisisusedtopredictwaveloadingandmotionresponsesforashiptravellingataconstantspeedinregularobliquewaves.Thecombineddiffractionandradiationperturbations,causedbythesteadyforwardspeedoftheshipandhermotions,areconsideredasadistributionofnormalvelocitiesonthewettedhullsurface.Theship-hullboundaryconditionisexactlyfulfilledbyexpressingthefluidnormalvelocitiesasafiniteseriesintermsofthebodygeometryandtheincidentwavepotential.Asfarastheauthorsareaware,nosimilarworkispublishedtodate.ThenewtheoryisappliedtopredictforcesandmotionsatforwardspeedforaWigleyship-hullinheadwavesandacatamaran-ferryinobliquewaves.PredictionsarecomparedwithpublishedtheoreticalandexperimentalresultsfortheWigleyship-hull,andthecomparisonisgood.Forthecatamaran,aself-propelledmodelisbuiltandtestedinthelargetowingtankandseakeepingbasinoftheChinaShipScientificResearchCentre,Wuxi

简介：Atime-domainKelvinsourcehigh-orderpanelmethodbasedonNURBSisdevelopedandappliedtosolvetheunsteadywave-makingproblems.Numericalresultsofinstantwaveresistanceandfreesurfaceelevationarepresentedandcomparedwiththeavailabyresultsbyotherauthors,forsubmergedspheroidandspherebeneaththefreesurfaceandforsurfaceshipofWigleymodelsmovingwithunsteadyspeed.Theagreementissatisfying.

简介：Inthispaperthecomplexstructureandpatternofshipsternflowdrivenbymulti-propellersissimulatednumericallybyusingRANSequationswithK-εturbulencemodelandpropellerliftingsurfacetheoryasessentialresearchtoolandcouplingthecomputercodeofshipsternflowtothecomputercodeofpropellerperformancepredictionthroughthemediumofbodyforce.Ashipmodelwithfourpropellersisselectedasthenumericalexample.Detailedcomputationalresultsarepresentedgraphicallyandthequalitativeandquantitativeanalysisismade.Finally,thecomparisonbetweenthecalculatedresultandtheavailableexperimentaldataismade.Theagreementbetweenthemissatisfactory.

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