Preprints
https://doi.org/10.5194/egusphere-2024-1634
https://doi.org/10.5194/egusphere-2024-1634
20 Jun 2024
 | 20 Jun 2024
Status: this preprint is open for discussion.

Equilibrium distance from long-range dune interactions

Jean Vérité, Clément Narteau, Olivier Rozier, Jeanne Alkalla, Laurie Barrier, and Sylvain Courrech du Pont

Abstract. Flow perturbations induced by dune topography affect sediment transport locally, but can also be felt over long distances altering the dynamics of isolated neighbouring dunes downstream. In order to work under optimal conditions that eliminate transverse flow components, collisions and mass exchange between dunes, we study here these long-range interactions using a 2D numerical model where two equal-sized dunes lying on a non-erodible bed are exposed to a symmetric reversing flow. Depending on the initial spacing, dunes either attract or repel each other, to eventually converge towards a steady-state spacing. This equilibrium distance decreases with flow strength and increases with period of flow reorientation and dune size. It is mainly controlled by the reversing dune shape and the structure of the turbulent wake it generates, which continuously modulates the mean shear stress on the downstream dune. Under multi-directional wind regimes, these long-range flow perturbations offer an alternative mechanism for wavelength selection in dune fields with non-erodible interdune areas. Within these dune fields, estimates of mean shear stress could be used to assess the relative migration rate and the state of attraction/repulsion between neighbouring dunes.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Jean Vérité, Clément Narteau, Olivier Rozier, Jeanne Alkalla, Laurie Barrier, and Sylvain Courrech du Pont

Status: open (until 01 Aug 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-1634', Anonymous Referee #1, 22 Jul 2024 reply
Jean Vérité, Clément Narteau, Olivier Rozier, Jeanne Alkalla, Laurie Barrier, and Sylvain Courrech du Pont
Jean Vérité, Clément Narteau, Olivier Rozier, Jeanne Alkalla, Laurie Barrier, and Sylvain Courrech du Pont

Viewed

Total article views: 184 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
134 39 11 184 5 5
  • HTML: 134
  • PDF: 39
  • XML: 11
  • Total: 184
  • BibTeX: 5
  • EndNote: 5
Views and downloads (calculated since 20 Jun 2024)
Cumulative views and downloads (calculated since 20 Jun 2024)

Viewed (geographical distribution)

Total article views: 170 (including HTML, PDF, and XML) Thereof 170 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 24 Jul 2024
Download
Short summary
Using a numerical model in 2D, we study how two identical dunes interact with each other when exposed to reversing winds. Depending on the distance between the dunes, they either repel or attract each other until they reach an equilibrium distance, which is controlled by the wind strength, wind reversal frequency and dune size. This process is controlled by the modification of wind flow over dunes of various shape, influencing the sediment transport downstream.