| Title: |
A lower-than-expected saltation threshold at Martian pressure and below |
| Authors: |
Andreotti, Bruno; Claudin, Philippe; Iversen, Jens, Jacob; Merrison, Jonathan, P; Rasmussen, Keld, R |
| Contributors: |
Mécanique, Matière Molle, Morphogénèse; Laboratoire de physique de l'ENS - ENS Paris (LPENS); Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL; École normale supérieure - Paris (ENS-PSL); Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL); Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL); Physique et mécanique des milieux hétérogènes (PMMH); Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris); Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité); Aarhus University Aarhus; European Project: 654208,H2020-INFRAIA-2014-2015,H2020-INFRAIA-2014-2015,EPN2020-RI(2015) |
| Source: |
ISSN: 0027-8424. |
| Publisher Information: |
CCSD; National Academy of Sciences |
| Publication Year: |
2021 |
| Subject Terms: |
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology |
| Description: |
38 pages, 21 figures ; International audience ; 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. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
info:eu-repo/semantics/altIdentifier/arxiv/2104.05341; info:eu-repo/grantAgreement//654208/EU/EUROPLANET 2020 Research Infrastructure/EPN2020-RI; ARXIV: 2104.05341 |
| DOI: |
10.1073/pnas.2012386118 |
| Availability: |
https://hal.science/hal-03940326; https://hal.science/hal-03940326v1/document; https://hal.science/hal-03940326v1/file/2104.05341.pdf; https://doi.org/10.1073/pnas.2012386118 |
| Rights: |
https://about.hal.science/hal-authorisation-v1/ ; info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.C7F76987 |
| Database: |
BASE |