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An erosion criterion for gravel‐bed rivers
Author(s) -
Naden Pamela
Publication year - 1987
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.3290120110
Subject(s) - flume , turbulence , geology , drag , erosion , mechanics , geotechnical engineering , range (aeronautics) , lift (data mining) , context (archaeology) , flow (mathematics) , shear stress , geomorphology , physics , engineering , computer science , aerospace engineering , paleontology , data mining
A theoretically‐based erosion criterion is developed for gravel‐bed rivers which incorporates the effect of both grain geometry and turbulent velocity fluctuations. It is derived from a balance of instantaneous drag, lift, and gravity forces operating on individual grains and is calculated for spherical grains arranged in three distinct geometries. To accommodate the temporal variation in bed shear stress, the model includes a stochastic element based on the characteristics of turbulence derived from the flume evidence of McQuivey (1973a, b). In terms of the Shields parameter, results show reasonable agreement with the range of observations quoted from the field and with the experimental data of Fenton and Abbott (1977). Finally, the argument is generalized to cover applications in the wider context of field conditions including a range of grain sizes and flow conditions.