Grain shape effects in bed load sediment transport
Name
grain_shape_eartharxiv.pdf
Description
Accepted version
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894.59 KB
Format
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Checksum (MD5)
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Author(s)
Deal, Eric
Venditti, Jeremy G
Benavides, Santiago J
Bradley, Ryan
Zhang, Qiong
Kamrin, Ken
Perron, J Taylor
Date Issued
January 12, 2023
Journal
Nature
Publisher
Springer Science and Business Media LLC
Citation
Deal, Eric, Venditti, Jeremy G, Benavides, Santiago J, Bradley, Ryan, Zhang, Qiong et al. 2023. "Grain shape effects in bed load sediment transport." Nature, 613 (7943).
Version
Author's final manuscript
Abstract
Bed load sediment transport, in which wind or water flowing over a bed of sediment causes grains to roll or hop along the bed, is a critically important mechanism in contexts ranging from river restoration1 to planetary exploration2. Despite its widespread occurrence, predictions of bed load sediment flux are notoriously imprecise3,4. Many studies have focused on grain size variability5 as a source of uncertainty, but few have investigated the role of grain shape, even though shape has long been suspected to influence transport rates6. Here we show that grain shape can modify bed load transport rates by an amount comparable to the scatter in many sediment transport datasets4,7,8. We develop a theory that accounts for grain shape effects on fluid drag and granular friction and predicts that the onset and efficiency of transport depend on the coefficients of drag and bulk friction of the transported grains. Laboratory experiments confirm these predictions and reveal that the effect of grain shape on sediment transport can be difficult to intuit from the appearance of grains. We propose a shape-corrected sediment transport law that collapses our experimental measurements. Our results enable greater accuracy in predictions of sediment transport and help reconcile theories developed for spherical particles with the behaviour of natural sediment grains.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1038/s41586-022-05564-6
