沙粒空中碰撞對風(fēng)沙躍移運動的影響.pdf

1、蘭州大學(xué)碩士學(xué)位論文沙?？罩信鲎矊︼L(fēng)沙躍移運動的影響姓名：姚建林申請學(xué)位級別：碩士專業(yè)：力學(xué)固體力學(xué)指導(dǎo)教師：黃寧20060501蘭州大學(xué)碩止學(xué)位論文AbstractSandmovementunderwindflowiSoneimportantphysicalprocessofwinderosionandsand／duststormswhichhaveseverelyimpactedthenaturalenvironmentandhum

2、anactivityInrecentyearsthedisastersduetothewindblownsandmovementhavebeingdevotedmuchattentioninChinaItiSconsideredcrucialtoprofoundlystudythewind—blownsandmovementmechanismforoverallunderstandingandpreventingwind—blownmo

3、vementandscientistshavedonealOtofWOrkonitHowevermanyformerscholarshadnottakenaccountoftheinfluenceofsaltatingparticle’midaircollisionwhentheycalculatethesandtransportrateofsaltatingparticleThemid—airinter—particlecollisi

4、ongenerallyisneglectedinaeoliansakationbecauseitiSastochasticandcomplexprocessInordertoexactlyestimatetheprobabilityofamid—airinterparticlecollisionforasaltatingparticleinasteady—statesaltationcloud，aphysicalmodelthatcan

5、predictthisprobabilityiSdevelopedbasedonthemodelsofSorensenandMcEwanf1996)1andZhangYali(2005)例Inourmodel，asetofexperimentallydeterminedsaltationcloudwindprofiles，whicharenotablynon—logarithmic，areemployedTheresultsshowth

6、at，comparedwiththeresultofthemid—aircollisionprobabilityinlogarithmwindspeedthecollisionprobabilityobtainedwithexperimentwindvelocityiSsmallerthantheonewithlogarithmwindspeedFinally，asimplemodel，whichisusedtocalculatesal

7、tatingparticles’velocitydiversityinmid—aircollision，issetupthroughhardballmodelCombiningwiththemodelofcollisionprobability，saltatingparticle’sandtransportratewhichvarieswithheightandmassfluxwhichvarieswithfrictionvelocit

8、yarecalculatedinmidaircollisionComparedwiththeresultwhenmidaircollisioniSnotconsidereditsuggeststhatthediversityiSlessthanthatofthisthesisSoiSthediversityofmassfluxwithfrictionvelocityInthemeantime，theresultsshowthatthem

9、idairinterparticlecollisionhasobviouseffectsonwindblownsandsaltationTherefore，theinfluenceofsakatingparticlecollidesinthemidaircannotbeignoredwhenstudyingsandtransportrateofsaltatingsandKeywords：saltationthecollisionprob