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Accueil > Équipes > Equipe MEIGE > Thèmes de recherche > Processus de couche limite & turbulence géophysique > Interaction couche limite - transport de sédiment

Sediment transport over dunes

(D. Hurther)

One of the most challenging scientific defeat of geophysical flow-driven sediment transport in fluvial, estuarine and coastal environments, resides in the elucidation of the flow mechanism at the origin of bedform development, evolution and migration (as bed ripples, dunes, anti-dunes, bars,...). This knowledge directly impacts our ability to predict flooding levels during climatic extreme flow events. In this context, Naqshband et al. (2014a, 2014b, 2017) provided the first quantitative evidence of the spatial phase-lag between sediment transport rate and the dune geometry explaining the transition from the "Equilibrium dune regime" to the "Upper Stage Plane bed regime" (also called "sheet flow regime"). These results were acknowledged by the American Geophysical Union (EOS 2014, Vol. 95, No.38, 23) as one of the most promising contributions in year 2014. New bedform experiments with LEGI are ongoing until mid 2020 with U. Wageningen (S. Naqshband, T. Hoïtink) to tackle the flow mechanism behind the transition from the ripple regime to the dune regime occuring at much lower flow stage.

Non-equilibrium dune experiments with LEGI (D. Hurther) at U. Wageningen : physical mechanisms behind the transition from the "Equilibrium-Dune regime" to the "Upper Stage Plane Bed regime" as a sheet flow.

Funding :
Bed-FormFlood project (Dutch Technology Foundation STW)

PhD Student and Post-doc
S. Naqshband (PhD at U. of Twente, The Netherlands)-collaboration with J.S. Ribberink
S. Naqshband (Post-doc at U. of Wageningen, The Netherlands)-collaboration with T. Hoïtink

Naqshband S., Hoitink A. J. F., Mcelroy B., Hurther D. and Hulscher S. J. M. H.. (2017) A Sharp View on River Dune Transition to Upper Stage Plane Bed. Geophysical Research Letters, American Geophysical Union, 〈10.1002/2017GL075906〉.
Naqshband S, Ribberink, J. S, Hurther D., Barraud, P.A., and Hulscher, S.J.M.H. (2014). Experimental evidence for turbulent sediment flux constituting a large portion of total sediment flux along migrating sand dunes. Geophysical Research Letters. doi : 10.1002/2014GL062322.
Naqshband S, Ribberink, J. S, Hurther D. and Hulscher, S.J.M.H. (2014). Bed load and suspended load contributions to migrating sand dunes in equilibrium. J. Geophys. Res. Earth Surface, 119, 1043-1063, doi : 10.1002/2013JF003043.
Eos, Vol. 95, No. 38, 23 (2014) « What drives migration of riverbed sand dunes ? ».