摘要
Therelationbetweengrain-sizedistributionofthebedandinsuspensionwascriticallyexaminedunderauniformflowvelocityof50cm/sovertwobeds:oneofmainlyfinesandsandtheotherofmediumsands.Twosections-one2.85mdownstreamandtheother6.35mdownstreamintheexperimentalchannel-wereselectedforsamplingtostudythegrain-sortingpatternintheverticaldirectionalongthedirectionoftransport.Theshapeandtypeofthegrain-sizedistributionpatternwerecriticallystudiedwithheightabovethebed.Thechangeinthedistributionpatternhasbeenattributedtothechangeoflocalbedroughnesscausingscouringagainsttheprotrudedrelativelycoarsegrainsonthebed.Suchtrendsareimportanttopredictthenatureofriverbedtopography.ThesandofBed-1initiallyexhibitsalog-skew-Laplacedistributionatdifferentheightsofsuspension.Thedistributionpattern,however,changesbutthischangingpatternisnotconsistentalongtheupstreamside.ForBed-2,whichinitiallyexhibitsalog-normaldistribution,thesamepatternpersistsfromtheheightofsuspensionat5cmupto20cm.Suchconsistencyinlog-normalityisalsoobservedatthedownstreampointsofmeasurement.Itisgenerallyexpectedthatthemeangrain-sizewouldreducewithincreasesofsuspensionheightbuttheresultsoftheexperiments,insomeoccasions,differsignificantlyfromthegradualfiningupwardtrend.Thisresulthasbeenattributedtolocalchangesofbedroughnessarisingfromtheprotrudedrelativelycoarsegrainscausingeddies,scouring,andturbulentphenomenawhichmovescoarseparticleshigherinsuspensionaddingacoarsetailtothedistributionincreasingthemeangrain-size.
出版日期
2017年03月13日（中国期刊网平台首次上网日期，不代表论文的发表时间）
