Experimental and numerical evidence for intrinsic nonmigrating bars in alluvial channels
@article{Crosato2011ExperimentalAN, title={Experimental and numerical evidence for intrinsic nonmigrating bars in alluvial channels}, author={Alessandra Crosato and Erik Mosselman and Frehiwot Beidmariam Desta and Wim S.J. Uijttewaal}, journal={Water Resources Research}, year={2011}, volume={47} }
Alternate bars in straight alluvial channels are migrating or nonmigrating. The currently accepted view is that they are nonmigrating if the width‐to‐depth ratio is at the value of resonance or if the bars are forced by a persistent local perturbation. We carried out 2‐D numerical computations and a long‐duration mobile‐bed flume experiment to investigate this view. We find that nonmigrating bars can also occur in straight channels without resonant width‐to‐depth ratio or steady local…
73 Citations
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References
SHOWING 1-10 OF 56 REFERENCES
Simple physics‐based predictor for the number of river bars and the transition between meandering and braiding
- Geology
- 2009
The number of bars that form in an alluvial channel cross section can be determined from a physics‐based linear model for alluvial bed topography. The classical approach defines separators between…
Alternate bars in and meandering of alluvial rivers
- Physics
- 1983
The paper presents a linear perturbation analysis of a horizontal two-dimensional mathematical model for the flow and bed topography in straight alluvial rivers with dominant bed-load. A sediment…
Free–forced interactions in developing meanders and suppression of free bars
- PhysicsJournal of Fluid Mechanics
- 1990
The coexistence of migrating alternate (free) bars, spontaneously developing in erodible channels as a result of an instability process, with steady point bars, forced by curvature in meandering…
Bend theory of river meanders. Part 1. Linear development
- GeologyJournal of Fluid Mechanics
- 1981
Instability of the alternate-bar type in straight channels has long been identified as the cause of fluvial meandering. The condition of inerodible sidewalls, however, does not allow a meandering…
Weakly nonlinear theory of regular meanders
- MathematicsJournal of Fluid Mechanics
- 1992
Flow and bed topography in a regular sequence of meanders is shown to be strongly influenced by nonlinear effects within a fairly wide range of aspect ratios of the channel and meander wavenumbers.…
Alternating bar instabilities in unsteady channel flows over erodible beds
- PhysicsJournal of Fluid Mechanics
- 2004
Channel flows over erodible beds are susceptible to instabilities of the coupled fluid and sediment flow equations. The most dangerous mode usually takes the form of a migrating alternating bar…
The initial instability and finite-amplitude stability of alternate bars in straight channels
- Environmental Science, Physics
- 1990
Instability and river channels
- PhysicsJournal of Fluid Mechanics
- 1969
A linearized stability analysis of the flow of water in a channel with a loose bed and straight banks is described. It is assumed that the wavelength of the perturbations, which develop into meanders…
Bed deformation in curved alluvial channels
- Engineering
- 1985
Recent research activities at the Delft Hydraulics Laboratory and the Delft University of Technology have increased the understanding of the large-scale bed deformation in alluvial rivers with…
On the cause and characteristic scales of meandering and braiding in rivers
- Environmental ScienceJournal of Fluid Mechanics
- 1976
A stability analysis of meandering and braiding perturbations in a model alluvial river is described. A perturbation technique, involving a small parameter representing the ratio of sediment…