Probabilistic Modeling of Bed-load Composition

Ian Kenneth McEwan, M. Sorensen, J. Heald, S. J. Tait, G. J. Cunningham, D. Goring, B. B. Willetts

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    30 Citations (Scopus)

    Abstract

    This paper proposes that the changes which occur in composition of the bed load during the transport of mixed-grain-size sediments are largely controlled by the distributions of critical entrainment shear stress for the various size fractions. This hypothesis is examined for a unimodal sediment mixture by calculating these distributions with a discrete particle model and using them in a probabilistic calculation of bed-load composition. The estimates of bed-load composition compare favorably with observations of fractional transport rates made in a laboratory flume for the same sediment, suggesting that the hypothesis is reasonable. The analysis provides additional insight, in terms of grain mechanics, into the processes that determine bed-load composition. These insights strongly suggest that better prediction methods will result from taking account of the variation of threshold within size fractions, something that most previous studies have neglected.

    Original languageEnglish
    Pages (from-to)129-139
    Number of pages10
    JournalJournal of Hydraulic Engineering
    Volume130
    Issue number2
    DOIs
    Publication statusPublished - Feb 2004

    Keywords

    • sediment
    • entrainment
    • probabilistic models
    • bed load
    • grain size
    • shear stress
    • CRITICAL SHEAR-STRESS
    • BEDLOAD TRANSPORT
    • GRADED SEDIMENT
    • FRICTION ANGLE
    • SIMULATION
    • MIXTURES
    • STREAMS
    • UNIFORM
    • MOTION
    • SIZE

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