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Effect of flow depth and velocity on the scales of macroturbulent structures in gravel‐bed rivers
Author(s) -
Marquis Geneviève A.,
Roy André G.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028420
Subject(s) - geology , flow (mathematics) , range (aeronautics) , scaling , flow velocity , sampling (signal processing) , geodesy , hydrology (agriculture) , geotechnical engineering , geometry , mechanics , physics , mathematics , optics , materials science , detector , composite material
Laboratory and field data show that the length of macroturbulent structures consistently scales with flow depth ( Y ). Scalings with average streamwise flow velocity ( U ) only exist for laboratory data. Our aim is to establish the relations between macroturbulent structures, low‐speed wedges and ejections, and U and Y in gravel‐bed rivers. Fifteen velocity profiles covering a wide range of U while controlling for Y were measured. The duration (time interval between the beginning and the end of an event) and length (distance between two successive similar events) of the macroturbulent events are analyzed. Strong scalings of the duration and length of the low‐speed wedges and ejections exist for Y . Ejection length is strongly related to U . Because the sampling design ensured the statistical independence between U and Y , these results should provide robust estimates of the scalings of macroturbulent structures in gravel‐bed rivers.