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Vertical sorting within dune structure

dc.contributor.authorAbdel-Motaleb, Mohamed M. M., author
dc.contributor.authorGessler, Johannes, advisor
dc.contributor.authorMolinas, Albert, committee member
dc.contributor.authorRichardson, E. V., committee member
dc.contributor.authorZachmann, D. W., committee member
dc.date.accessioned2019-03-06T20:04:14Z
dc.date.available2019-03-06T20:04:14Z
dc.date.issued1993
dc.description.abstractVertical sorting of sediment mixtures within dune structures was measured experimentally by conducting three types of experiments: running water experiments, still water experiments, and air experiments. Five different sediment mixtures with known initial gradations were used. The median grain diameters for the five sediment mixtures were between 0.35 mm and 0.86 mm, the geometric standard deviations of the same sediment mixtures were between 2.30 and 2.9. In the running water experiments, each experiment was continued until the dunes were fully developed down the flume. Then each dune was sampled along several horizontal layers. In the still water experiments, a delta shape was deposited, foreset by foreset, following one another in a continuous way. In the air experiments, the sand mixture was deposited as in the still water experiments. These experiments were to study the effect of the gravitational force on the vertical sorting process. The results of the running water experiments showed clearly demonstrated the vertical sorting process (vertical reduction in the sediment grain diameter) within the two-dimensional dunes. Also, the still water and air experiments showed the importance of the hydrodynamic force on the sorting process. A prediction equation relating the median grain diameter within the dune structure in the vertical direction to the back flow velocity on the lee face of the dune and the submerged weight of the sediment particle was used to calculate the vertical median grain diameter for the two-dimensional dune and compared with the measured data. Five dimensionless parameters were tested to correct the error in the predicted values. The dimensionless grain diameter gave the best result. Other sets of laboratory and field data for a point bar and three-dimensional dunes showed the sorting phenomenon. Calculated values for the vertical median grain diameter for the three-dimensional dune computed using the prediction equation agreed reasonably well with the observed values.
dc.format.mediumdoctoral dissertations
dc.identifier.urihttps://hdl.handle.net/10217/194269
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relationCatalog record number (MMS ID): 991021559619703361
dc.relationTC175.2.A34 1993
dc.relation.ispartof1980-1999
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subject.lcshSediment transport
dc.subject.lcshBed load
dc.subject.lcshSedimentation and deposition
dc.titleVertical sorting within dune structure
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineCivil Engineering
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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