The cross-sectional shape of tidal sandbanks: modeling and observations
Roos, Pieter C., Hulscher, Suzanne J.M.H., Knaapen, Michiel A.F. and Van Damme, Ruud M.J. (2004) The cross-sectional shape of tidal sandbanks: modeling and observations. Journal of Geophysical Research, 109, (F2), F02003. (doi:10.1029/2003JF000070).
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To improve our understanding of tidal sandbank dynamics, we have developed a nonlinear morphodynamic model. A crucial property of the model is that it fully resolves the dynamics on the fast ( tidal) timescale, allowing for asymmetric tidal flow with an M-0, M-2, and M-4 component. This approach, extending earlier research on the formation of tidal sandbanks, leads to equilibrium profiles. Their heights ( 60 - 90% of the water depth) and shapes are controlled by the mode of sediment transport and the hydrodynamic conditions. Bed load transport under symmetrical tidal conditions leads to high spiky banks. Several mechanisms tend to lower and smooth these profiles, such as the relaxation of suspended sediment, wind wave stirring, and tidal asymmetry. This last causes the profiles to be asymmetric, as well. The morphodynamic equilibrium expresses a tidally averaged balance between a destabilizing flux due to fluid drag and the downslope transport induced by both tidal flow and wind wave stirring. The modeled profiles are in fair agreement with observations from the North Sea.
|Keywords:||morphodynamics, tidal sandbanks, equilibrium profiles, southern North Sea, connected sand ridges, dynamics, banks, transport, bed, waves|
|Subjects:||G Geography. Anthropology. Recreation > GC Oceanography|
|Divisions:||University Structure - Pre August 2011 > School of Civil Engineering and the Environment
University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
|Date Deposited:||28 Apr 2006|
|Last Modified:||28 Jun 2012 10:11|
|Contact Email Address:||P.C.Roos@ctw.utwente.nl|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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