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Unsteady flow in straight alluvial streams: modification of individual dunes

Published online by Cambridge University Press:  19 April 2006

Jørgen Fredsøe
Jørgen Fredsøe
Affiliation:
Institute of Hydrodynamics and Hydraulic Engineering, Technical University of Denmark, DK 2800 Lyngby/Copenhagen
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Abstract

Changes in dune properties due to a sudden change in the water discharge are analysed. The transport of sediment is assumed to occur mainly as bed load and the square of the Froude number must be much smaller than unity. The theory is based on similarity in the bed-shear distribution close to the dune top just before and just after the change in the water discharge. The model is found to agree with laboratory experiments. Further, by use of this model, flow in a river where the water discharge oscillates weakly around a constant mean value has been treated. Hereby the variation in the phase differences between sediment transport, water depth and water discharge with the period of the oscillation is calculated. The results agree qualitatively with observations.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 91 , Issue 3 , 11 April 1979 , pp. 497 - 512
Copyright
© 1979 Cambridge University Press

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References

Allen, J. R. L. 1976a Computational models for dune time-lag: General ideas, difficulties and early results. Sediment. Geol. 15, 1–53.Google Scholar
Allen, J. R. L. 1976b Bed forms and unsteady processes: some concepts of classification and response illustrated by common one-way types. Earth Surface Processes 1, 361–374.Google Scholar
Carey, C. & Keller, M. D. 1957 Systematic changes in the beds of alluvial rivers. Proc. A.S.C.E. 83 (HY4), 1–24.Google Scholar
Einstein, H. A. 1950 The bed-load function for sediment transport in open channel flows. U.S. Dept of Agric. Tech. Bull. no. 1026.Google Scholar
Engelund, F. 1978 Hydraulic resistance for flow over dunes. I.S.V.A., Tech. Univ. Denmark, Prog. Rep. no. 44.Google Scholar
Engelund, F. & Fredsøe, J. 1976 A sediment transport model for straight alluvial channels. Nordic Hydrol. 7, 293.Google Scholar
Engelund, F. & Hansen, E. 1972 A Monograph on Sediment Transport in Alluvial Streams. Copenhagen: Technical Press.
Fredsøe, J. 1974 On the development of dunes in erodible channels. J. Fluid Mech. 64, 1–16.Google Scholar
Fredsøe, J. 1975 The friction factor and height-length relations in flow over a dune-covered bed. I.S.V.A., Tech. Univ. Denmark, Prog. Rep. no. 37.Google Scholar
Fredsøe, J. 1976 Sediment inertia as cause of river anti-dunes. Discussion. Proc. A.S.C.E. 102 (HY1), 99–102.Google Scholar
Gee, D. M. 1973 Sediment transport in non-steady flow. Univ. Calif. Berkeley, Rep. HEL 22–3.Google Scholar
Leopold, L. B., Wolman, M. G. & Miller, J. P. 1964 Fluvial Processes in Geomorphology. W. H. Freeman.
Meyer-Peter, E. & Müller, R. 1948 Formulas for bed-load transport. Proc. 3rd Meeting I.A.H.R.
Simons, D. B., Richardson, E. V. & Haushild, W. L. 1962 Depth-discharge relations in alluvial streams. Proc. A.S.C.E. 88 (HY5), 57–72.Google Scholar
Yalin, M. S. 1972 Mechanics of Sediment Transport. Pergamon.