Service interruption on Monday 11 July from 12:30 to 13:00: all the sites of the CCSD (HAL, Epiciences, SciencesConf, AureHAL) will be inaccessible (network hardware connection).
Skip to Main content Skip to Navigation
Journal articles

Development and steady states of transverse dunes: A numerical analysis of dune pattern coarsening and giant dunes

Abstract : We investigate the development and steady states of transverse dunes for ranges of flow depths and velocities using a cellular automaton dune model. Subsequent to the initial bed instability, dune pattern coarsening is driven by bed form interactions. Collisions lead to two types of coalescence associated with upstream or downstream dominant dunes. In addition, a single collision-ejection mechanism enhances the exchange of mass between two adjacent bed forms (throughpassing dunes). The power law increases in wavelength and amplitude exhibit the same exponents, which are independent of flow properties. Contrary to the wavelength, dune height is limited not only by flow depth but also by the strength of the flow. Superimposed bed forms may propagate and continuously destabilize the largest dunes. We identify three classes of steady state transverse dune fields according to the periodicity in crest-to-crest spacing and the mechanism of size limitation. In all cases, the steady state is reached and maintained through the dynamic equilibrium between flow strength and dune aspect ratio. In the limit of low flow strength, where it becomes the primary factor of size limitation, the bed shear stress in the dune trough regions is close to its critical value for motion inception. Comparisons with natural dune fields suggest that many of them may have reached a steady state. Finally, we infer that the sedimentary patterns in the model may be used to bring new constraints on the development of modern and ancient dune fields.
Document type :
Journal articles
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-03579552
Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Friday, February 18, 2022 - 10:45:13 AM
Last modification on : Sunday, February 20, 2022 - 3:32:43 AM
Long-term archiving on: : Thursday, May 19, 2022 - 6:35:37 PM

File

JGR Earth Surface - 2015 - Gao...
Publisher files allowed on an open archive

Licence

Copyright

Identifiers

Citation

Xin Gao, Clément Narteau, Olivier Rozier. Development and steady states of transverse dunes: A numerical analysis of dune pattern coarsening and giant dunes. Journal of Geophysical Research: Earth Surface, American Geophysical Union/Wiley, 2015, 120, pp.2200-2219. ⟨10.1002/2015JF003549⟩. ⟨insu-03579552⟩

Share

Metrics

Record views

24

Files downloads

3