A lower-than-expected saltation threshold at Martian pressure and below - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Proceedings of the National Academy of Sciences of the United States of America Année : 2021

A lower-than-expected saltation threshold at Martian pressure and below

Bruno Andreotti
Jens Jacob Iversen
Jonathan P Merrison
Keld R Rasmussen

Résumé

Aeolian sediment transport is observed to occur on Mars as well as other extraterrestrial environments, generating ripples and dunes as on Earth. The search for terrestrial analogues of planetary bedforms, as well as environmental simulation experiments able to reproduce their formation in planetary conditions, are powerful ways to question our understanding of geomorphological processes towards unusual environmental conditions. Here, we perform sediment transport laboratory experiments in a closed-circuit wind tunnel placed in a vacuum chamber and operated at extremely low pressures to show that Martian conditions belong to a previously unexplored saltation regime. The threshold wind speed required to initiate saltation is only quantitatively predicted by state-of-the art models up to a density ratio between grain and air of 4 × 10 5 , but unexpectedly falls to much lower values for higher density ratios. In contrast, impact ripples, whose emergence is continuously observed on the granular bed over the whole pressure range investigated, display a characteristic wavelength and propagation velocity essentially independent of pressure. A comparison of these findings with existing models suggests that sediment transport at low Reynolds number but high grainto-fluid density ratio may be dominated by collective effects associated with grain inertia in the granular collisional layer.
Fichier principal
Vignette du fichier
2104.05341.pdf (2.87 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03940326 , version 1 (16-01-2023)

Identifiants

Citer

Bruno Andreotti, Philippe Claudin, Jens Jacob Iversen, Jonathan P Merrison, Keld R Rasmussen. A lower-than-expected saltation threshold at Martian pressure and below. Proceedings of the National Academy of Sciences of the United States of America, 2021, 118 (5), pp.e2012386118. ⟨10.1073/pnas.2012386118⟩. ⟨hal-03940326⟩
12 Consultations
21 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More