简介:TheaddedresistanceofKVLCC2inshortandregularheadwaveshasbeenstudiedtheoreticallyandexperimentally.Modeltestsareperformedtodeterminehowwelltheasymptoticformula(Faltinsenetal.1980)predictsthetypicallevelofaddedresistanceinshortwaves.Becausetheasymptoticformulaneglectstheeffectsofshipmotions,itiscombinedwiththeoreticalmethodstocalculatetheaddedresistanceinlongwavesusinganfunctiontopredicttheaddedresistanceintheintermediatewavelengthregionwherebothshipmotionsandwavereflectionareimportant.Auniquefeatureofthisexperimentisthattheshipmodelisdividedintothreesegmentstoexploretheaddedresistancedistributionwithrespecttohullsegment.Thispaperdiscussesthesensitivityofexperimentalresultstothequalityoftheincidentregularheadwaves.Moreover,anovelprocedureforanalyzingaddedresistanceisdescribed.Finally,theexperimentallydeterminedaddedresistanceofKVLCC2iscomparedwiththeoreticalresults.Itisshownthattheaddedresistancefromthecombinedtheoreticalmethodsagreeswellwithexperimentalresultsinboththeintermediateandshortwaveregions.Theuseofhullsegmentsshowsthataddedresistanceisconcentratedprimarilyatthebow.
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简介:1碳交易碳交易是建立在《KyotoProtocol京都议定书》基础上的一种温室气体减排交易。《京都议定书》首先确定了温室气体的种类:二氧化碳(CO2)、甲烷(CH4)、氧化亚氮(N2O)、氢氟碳化物(HFCs)、全氟化碳(PFCs)、六氟化硫(SF6),以CO2为标准,其它五种温室气体折算成CO2当量进行交易。《京都议定书》为附件1国家制定了一个温室气体减排的量化标准,要求这些国家在2008-2012年之间必须完成规定的减排量,未完成的国家将受到联合国的惩罚。他们可以通过多种被联合国认可的方式完成规定的减排量,清洁发展机制是被采用最多的一种,几个主要附件1国家的减排标准如下:
简介:Whenabodynavigateswithcavityinshallowwater,bothflexiblefreesurfaceandrigidbottomwallwillproducegreatinfluencesonthecavityshapeandhydrodynamicperformances,andfurtheraffectthemotionattitudeandstabilityofthebody.Inthepresentwork,characteristicsofthenaturalcavitatingflowarounda2-Dsymmetricalwedgeinshallowwaterwereinvestigatedandtheinfluencesoftwotypeboundariesontheflowpatternwereanalyzed.TheVolumeOfFluid(VOF)multiphaseflowmethodwhichissuitableforfreesurfaceproblemswasutilized,coupledwithanaturalcavitationmodeltodealwiththemass-transferprocessbetweenliquidandvaporphases.Withintherangeofthecavitationnumberforcomputation(0.07-1.81),thecavityconfigurationswouldbedividedintothreetypes,viz.,stabletype,transitiontypeandwake-vortextype.Inthisarticle,theshapesofthefreesurfaceandthecavitysurface,andthehydrodynamicperformanceofthewedgewerediscussedundertheconditionsofrelativelysmallcavitationnumber(<0.256).Thepresentnumericalcavitylengthsgenerallyaccordwithexperimentaldata.Whenthecavitationnumberwasdecreased,thecavitywasfoundtobecomelongerandthicker,andthescopeofthedeformationofthefreesurfacealsograduallyextends.Thefreesurfaceandtheuppercavitysurfacecorrespondfairlytotheirshapes.However,thelowersideofthecavitysurfacewasratherleveledduetotheinfluenceofwallboundary.Theliftanddragcoefficientsofthis2-Dwedgebasicallykeeplinearrelationswiththenaturalcavitationnumbersmallerthan0.157,whereasdirectproportionfordragandinverseproportionforlift.