The Role of Instantaneous Forces in Particle Movement

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dc.contributor.authorGreer, Kristaen
dc.contributor.committeecochairDancey, Clinton L.en
dc.contributor.committeecochairDiplas, Panayiotisen
dc.contributor.committeememberLittle, John C.en
dc.contributor.departmentCivil Engineeringen
dc.date.accessioned2014-03-14T20:44:56Zen
dc.date.adate2006-10-02en
dc.date.available2014-03-14T20:44:56Zen
dc.date.issued2006-08-31en
dc.date.rdate2007-10-02en
dc.date.sdate2006-09-07en
dc.description.abstractMany methods and equations have been developed to predict bed load transport rates, most of which use some comparison between shear stress and critical shear stress. The critical shear stress is determined by the point of incipient motion. Researchers have attempted to predict bed load transport both deterministically with mean parameters and stochastically attempting to take into account the fluctuations of velocity at points near threshold. This work attempts to show that more than simple force balances are needed to determine the point at which a particle will move. Turbulent fluctuations in velocity seem to have an effect of particle entrainment. The fluctuations in velocity can be several times greater than their time averaged counterparts. These short durations of high velocity often result in particle movement even though the mean flow may be less than or very near critical conditions. Through experiments of a single spherical particle on a simple bed geometry in air without the effects of water, it is shown that time duration of force has an effect on entrainment. This shows that there may be a constant force-time combination, or impulse, required to entrain sediment.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-09072006-083326en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09072006-083326/en
dc.identifier.urihttp://hdl.handle.net/10919/34957en
dc.publisherVirginia Techen
dc.relation.haspartThesis_Sept22.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectincipient motionen
dc.subjectsediment transporten
dc.subjectimpulseen
dc.subjectelectromagneten
dc.titleThe Role of Instantaneous Forces in Particle Movementen
dc.typeThesisen
thesis.degree.disciplineCivil Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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