Journal ArticleDOI
Initial Instability of Fine Bed Sand
TLDR
In this paper, the initial entrainment characteristics of fine bed sand are objectively defined in terms of the measured distributions of critical instantaneous bed shear stress associated with the observed movement of individual surface grains.Abstract:
The initial entrainment characteristics of fine bed sand are objectively defined in terms of the measured distributions of critical instantaneous bed shear stress associated with the observed movement of individual surface grains. Critical flow conditions are then predicted by equating the lower extremes in these characteristic critical shear stress distributions to the upper extremes in the distribution of instantaneous bed shear stress produced by the particular type of background flow under consideration. The method is applied to the case of two-dimensional channel flow over a flat bed and yields sufficiently consistent results to suggest an extension to Shields' curve for small grain Reynolds numbers. The detailed experimental observations clearly illustrate the important role played by bed region turbulence in the interaction process between the fluid and the mobile bed grains constituting the deformable boundary.read more
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Dissertation
Three-dimensional unsteady modeling of clear-water scour in the vicinity of hydraulic structures: Lagrangian and Eulerian perspectives
TL;DR: In this paper, Sotiropoulos et al. presented a Ph.D. dissertation on civil engineering at the University of Minnesota, Bloomington, MN. Major: Civil Engineering.
Dissertation
“MEMORY STRESS”: physical and mathematical modelling of the influence of water-working on sediment entrainment and transport
TL;DR: In this paper, the effects of memory stress on sediment entrainment and transport in river flumes have been quantified via robust physical and mathematical modelling, and a framework for correcting existing graded sediment formulae for memory stress has been effectively developed using a scaling of the granular scale roughness parameter, An.
Journal ArticleDOI
Bed-load transport rate based on the entrainment probabilities of sediment grains by rolling and lifting
Jun-de Li,Jian Sun,BinLiang Lin +2 more
TL;DR: In this article, the entrainment probabilities of the rolling and lifted sediment grains were used to predict the bed-load sediment transport rate and the bed layer thickness at a high bedload transport rate.
Journal ArticleDOI
A meso-scale gravel tracer model for large gravel-bed rivers
TL;DR: In this article, a simplified numerical gravel tracer model is presented that utilizes the flow field calculated by a three-dimensional hydrodynamic model, operating on the meso-scale, predicting pathways and velocities.
Journal ArticleDOI
Sediment Bed-Load Transport: A Standardized Notation
Ulrich Zanke,Aron Roland +1 more
TL;DR: In this paper, a structural formula comparison is made by transferring altogether 13 transport functions into a standardized notation, and it is shown that these approaches lead to essentially the same basic formula for the main variables.