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1、Current:ProfilesextendoverentiredepthcUNoncohesivesedimenttransportinwavesandcurrentsWaves:Outerorbitalmotion~PotentialflowTurbulenceandsedimentrestrictedtothinwaveboundarylayercUCombinedwavesandcurrentIncreasededdyvicositynearthebedretardstheflow.Increas
2、edflowresistance.Apparentwaveroughness:UInthesurfzone:Wavebreakingproducesturbulence,suspendedsedimentovertheentirewaterdepthWaveboundarylayerSurfzoneturbulenceTurbulenceinspillingbreakerhighenergydissipationandproductionofturbulence:ProductionatRollerDow
3、nwarddiffusionDissipationResult:muchhigherturbulencelevelinthewatercolumnTurbulenceandsedimentexchangefactor:Non-breakingwaves:highnearthebedBreakingwaves:Highnearthebedandawayfromthebed:’Bottleneck’SedimentconcentrationprofilesWavesonly:Veryclosetothebed
4、~cmWavesandcurrent:higherintothewatercolumnWithbreakingwaves:overentirewatercolumnDrift:Twowayofdescribingdrift,samephenomenon1.Eulerian,lookatapointBelowtroughlevel:Watermotionbackandforth-Result:nomeanmotionDrift:Twowayofdescribingdrift,samephenomenon1.
5、Eulerian,lookatapointBetweencrestandtrough:Forward:waterBackward:nowater-ResultforwardvelocityDrift:Twowayofdescribingdrift,samephenomenon1.Lagrangian,lookatawaterparticle,ellipticalpathBelowcrest:Forwardmotion,followsthewave,longerdurationBelowtrough:Bac
6、kwardmotion,againstthewave,shorterdurationUndercrest:particlehigh,largerforwardvelocityUndertrough:particlelow,smallerbackwardvelocity-Result:meanforwardmotionInsideawaveDeepwaterShallowwaterEulerianorLagrangiandrift,samedischarge,Butflowtowardsthecoastis
7、zero:offshoredirectedreturncurrentDoesdriftaffectsuspendedsediment-??Yes,theconcentrationprofileisstretchedunderthecrest,andthesedimenttravelswith/againstthewaveRequireshigherorderrepresentationofvelocityfieldStreaming–momentumtransferVerticalfluxofhorizo
8、ntalmomentum:cf.Reynoldsstress:Purewavemotionwithoutloss:So::noShearstressButthewaveboundarylayeriscausingadeficitdischarge,D,whichvariesalongthewaveandinducesanadditionalverticalvelocity,W0Butthewaveboundarylayeris