Analytical models for bar patterns and braiding threshold

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Analytical models for bar patterns and braiding threshold

Type

Hydromorphological models

Basic principles

Linearized fundamental equations for conservation of water mass and water flow momentum, time-averaged over all turbulent fluctuations, spatially averaged over water depth (2DH) or nor spatially averaged (3D). Linearized parameterized relation for effect of helical flow on bed shear stress direction. Linearized equilibrium sediment transport predictor or advection-relaxation equation for sediment transport. Linearized empirical relation for effect of sloping beds on sediment transport magnitude and direction. Linearized Exner equation for conservation of sediment mass.

Outputs

Number of bars per cross-section, bar length, bar stability.

Rivertypes

Related Pressures

Related Measures


Useful references

Selected software systems

REGMEANDER

Theoretical background

Blondeaux P. and Seminara G. (1983): Bed topography and instabilities in sinuous channels. In: River Meandering, Proc. Conf. Rivers 1983, New Orleans, Ed. C.M. Elliott, ASCE, 1984, pp.747-758.

Colombini M., Seminara G., Tubino M. (1987): Finite-amplitude alternate bars. J. Fluid Mech., 181, pp.213-232. http://dx.doi.org/10.1017/S0022112087002064

Crosato A. and Mosselman E. (2009): Simple physics-based predictor for the number of river bars and the transition between meandering and braiding, Water Resources Res., AGU, 45, W03424. http://onlinelibrary.wiley.com/doi/10.1029/2008WR007242/abstract

Struiksma N., Olesen K.W., Flokstra C., de Vriend H.J. (1985): Bed deformation in curved alluvial channels. J. Hydr. Res., IAHR, 23, (1), pp.57-79. http://www.tandfonline.com/doi/abs/10.1080/00221688509499377#.UZN6d8pIXoY

Sample applications