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Grain velocities in overland flow: A laboratory study
Author(s) -
Govers Gerard
Publication year - 1989
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290140605
Subject(s) - geology , grain size , flow (mathematics) , flow velocity , shear velocity , shear (geology) , surface finish , sediment , surface runoff , geotechnical engineering , mechanics , geomorphology , materials science , turbulence , petrology , composite material , physics , ecology , biology
In order to gain insight into the sediment transport process as it occurs in overland flow, velocities of fine to coarse sand grains were measured on beds of varying roughness. For all grain sizes, grain velocity can be well related to the shear velocity of the flow. However, the relationship is essentially linear for coarse grains, while there is a progressive increase of grain velocity for fine grains. The latter is not only due to the changing flow characteristics with height, but also to the fact that fine grains are transported at relatively greater heights above the bed at high shear velocities. The results explain some characteristics of earlier developed empirical transporting capacity relationships.