風(fēng)沙流躍移沙粒運(yùn)動(dòng)的若干基本問(wèn)題.pdf

1、蘭州大學(xué)碩士學(xué)位論文風(fēng)沙流躍移沙粒運(yùn)動(dòng)的若干基本問(wèn)題姓名：張亞麗申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：固體力學(xué)指導(dǎo)教師：黃寧20050501蘭業(yè)生蘭堡占蘭垡堡奎——AbstractIthasbeenfoundthattheprobabilitydensityofliftofforinitialspeedfunctionofsandejectingfromsandbedplaysacentralroleintheresearchofmechanismo

2、fwind—blownsandstolinkmicroandmacro—movementsofsandgrainsinawindflowManyscholarshaveresearchedthesaltatingparticle’SliR—offvelocityButthosestudychieflytakeaccountofthedistributionofverticallift—offvelocity，andignorethedi

3、stributionofsaltatingparticle’ShorizontalvelocityInthisarticle，weanalysisthemeasurementdatagainedbyParticleDynamicAnalyzer(PDA)measurementtechnology，andthroughfittingthedatawegetthe2Dprobabilitydistributionofthesaltating

4、particle’Slift—offvelocitywhichconsidersbothhorizontalandverticalvelocityThen，somesimulationsofsandsaltationonthebasisofthe2Dprobabilitydistributionareconductedtopredictthewindprofile，thesandfluxperunitareaandunittimevar

5、yingwitllheightandsandtransportrateinthewindblownsandfluxatdifferentflee—streamwindvelocitiesanddifferentdiametersofsandFinally，thenumericalresultsarecomparetotheformernumericalresultswithouttakingaccotmtofthedistributio

6、nofsaitatingparticle’ShorizontalvelocityTheresultsshowthatthewindprofiletakingaccountoftheprobabilitydistributionofthesaltatingparticle’Shorizontalandverticalvelocityisusuallylessthanthewindprofilewithouttakingaccountoft

7、heprobabilitydistributionofthesaltatingparticle’Shorizontalvelocity；thesandfluxperunitandunittimetakingaccountoftheprobabilitydistributionofthesaltatingparticle’Shorizontalandverticalvelocityatsametimeisgreaterthanthesan

8、dfluxperunitandunittimewithouttakingaccountoftheprobabilitydistributionofthesaltatingparticle’Shorizontalvelocity；thesandtransportratetakingaccountoftheprobabilitydistributionofthesaltatingparticle’Shorizontalandvertical

9、velocityatsametimeisgreaterthanthesandtransportratewithouttakingaccountoftheprobabilitydistributionofthesaltatingparticle’ShorizontalvelocityTherefore，theeffectofthesaitatingparticle’Shorizontalliftoffvelocityonthosemacr

10、oscopicquantitiesshouldn’tbeignoredThemid—airinterparticlecollisiongenerallyisneglectedinaeoliansaltationbecauseitisastochasticandcomplexprocessAtheoreticalsimulationmodelisdevelopedtocalculatetheprobabilityofmid—airinte

11、rparticlecollisionsinanaeoliansaltatingcloudThecollisionprobabilitiesintheascending，descendingstagesandthewholesaltationprocessarecalculatedforthesaltatingparticleswithdifferentliR—offvelocityatdifferentfreestream塒ndvelo