Saltation, the motion of sand grains in a sequence of ballistic
trajectories close to the ground, is a major factor for surface erosion,
dune formation, and triggering of dust storms on Mars. Although this
mode of sand transport has been matter of research for decades through
both simulations and wind tunnel experiments under Earth and Mars
conditions, it has not been possible to provide accurate measurements of
particle trajectories in fully developed turbulent flow. Here we
calculate the motion of saltating grains by directly solving the
turbulent wind field and its interaction with the particles. Our
calculations show that the minimal wind velocity required to sustain
saltation on Mars may be surprisingly lower than the aerodynamic minimal
threshold measurable in wind tunnels. Indeed, Mars grains saltate in 100
times higher and longer trajectories and reach 5-10 times higher
velocities than Earth grains do. On the basis of our results, we arrive
at general expressions that can be applied to calculate the length and
height of saltation trajectories and the flux of grains in saltation
under various physical conditions, when the wind velocity is close to
the minimal threshold for saltation.
%0 Journal Article
%1 WOS:000255534100004
%A Almeida, Murilo P
%A Parteli, Eric J R
%A Jr., Jose S Andrade
%A Herrmann, Hans J
%C 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA
%D 2008
%I NATL ACAD SCIENCES
%J PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF
AMERICA
%K critical flows; flows} granular particle-laden phenomena; transport; turbulent {aeolian
%N 17
%P 6222-6226
%R 10.1073/pnas.0800202105
%T Giant saltation on Mars
%V 105
%X Saltation, the motion of sand grains in a sequence of ballistic
trajectories close to the ground, is a major factor for surface erosion,
dune formation, and triggering of dust storms on Mars. Although this
mode of sand transport has been matter of research for decades through
both simulations and wind tunnel experiments under Earth and Mars
conditions, it has not been possible to provide accurate measurements of
particle trajectories in fully developed turbulent flow. Here we
calculate the motion of saltating grains by directly solving the
turbulent wind field and its interaction with the particles. Our
calculations show that the minimal wind velocity required to sustain
saltation on Mars may be surprisingly lower than the aerodynamic minimal
threshold measurable in wind tunnels. Indeed, Mars grains saltate in 100
times higher and longer trajectories and reach 5-10 times higher
velocities than Earth grains do. On the basis of our results, we arrive
at general expressions that can be applied to calculate the length and
height of saltation trajectories and the flux of grains in saltation
under various physical conditions, when the wind velocity is close to
the minimal threshold for saltation.
@article{WOS:000255534100004,
abstract = {Saltation, the motion of sand grains in a sequence of ballistic
trajectories close to the ground, is a major factor for surface erosion,
dune formation, and triggering of dust storms on Mars. Although this
mode of sand transport has been matter of research for decades through
both simulations and wind tunnel experiments under Earth and Mars
conditions, it has not been possible to provide accurate measurements of
particle trajectories in fully developed turbulent flow. Here we
calculate the motion of saltating grains by directly solving the
turbulent wind field and its interaction with the particles. Our
calculations show that the minimal wind velocity required to sustain
saltation on Mars may be surprisingly lower than the aerodynamic minimal
threshold measurable in wind tunnels. Indeed, Mars grains saltate in 100
times higher and longer trajectories and reach 5-10 times higher
velocities than Earth grains do. On the basis of our results, we arrive
at general expressions that can be applied to calculate the length and
height of saltation trajectories and the flux of grains in saltation
under various physical conditions, when the wind velocity is close to
the minimal threshold for saltation.},
added-at = {2022-05-23T20:00:14.000+0200},
address = {2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA},
author = {Almeida, Murilo P and Parteli, Eric J R and Jr., Jose S Andrade and Herrmann, Hans J},
biburl = {https://www.bibsonomy.org/bibtex/21886ed129776f63f4c39a7881fb0fc17/ppgfis_ufc_br},
doi = {10.1073/pnas.0800202105},
interhash = {96bbcd1fe04565ec12574533f46a7438},
intrahash = {1886ed129776f63f4c39a7881fb0fc17},
issn = {0027-8424},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF
AMERICA},
keywords = {critical flows; flows} granular particle-laden phenomena; transport; turbulent {aeolian},
number = 17,
pages = {6222-6226},
publisher = {NATL ACAD SCIENCES},
pubstate = {published},
timestamp = {2022-05-23T20:00:14.000+0200},
title = {Giant saltation on Mars},
tppubtype = {article},
volume = 105,
year = 2008
}