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Finite Amplitude of Free Alternate Bars With Suspended Load
Author(s) -
Bertagni Matteo Bernard,
Camporeale Carlo
Publication year - 2018
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2018wr022819
Subject(s) - amplitude , instability , bar (unit) , nonlinear system , wavelength , mechanics , perturbation (astronomy) , sediment transport , physics , geology , geotechnical engineering , sediment , optics , meteorology , geomorphology , quantum mechanics
River bars are macroscale sediment patterns, whose main geometrical features (wavelength and amplitude) depend on the mutual interactions between hydrodynamics and sediment transport. River bars develop as an instability of the plane bed to an infinitesimal perturbation, which grows in time to eventually reach a finite amplitude. We here determine, with reference to both bed and suspended loads, a closed form for the finite amplitude, through the nonlinear Center Manifold Projection technique. Results show that suspension plays a destabilizing role in bar instability, affecting both the bar wavelength (linear analysis) and the bar amplitude (weakly nonlinear analysis). This proves the importance of considering suspended load for practical purposes. The outcomes of the model are satisfactorily compared with field observations.