Journal ArticleDOI
A two-species model of aeolian sand transport
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TLDR
In this article, a model based on a discrete number of states is derived, which solves the problems of self-consistent and unstable solutions to the transport of sand by wind, which results from the equilibrium between the erosion of grains dragged by the flow and the resulting slow down of the wind velocity.Abstract:
The transport of sand by wind results from the equilibrium between the erosion of grains dragged by the flow and the resulting slow down of the wind velocity. The dynamical mechanisms governing the saturation of the sand flux are investigated theoretically. We first demonstrate that previous models, based on the assumption that all the grains have the same trajectory, are either not self-consistent or lead to unstable solutions. A model based on a discrete number of states is derived, which solves these problems. Two well-defined species of grain appear, which correspond to saltons (high-energy grains) and reptons (grains ejected from the sand bed by the impact of saltons). They play specific roles: the negative feedback of the transport on the wind is limited to the reptation layer while most of the transport is due to saltation. The model is further simplified, benefiting from the existence of these two species and the dependencies of the threshold velocity, the saturated flux, the aerodynamic roughness and the saturation length are derived and compared to experimental measurements.read more
Citations
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Journal ArticleDOI
Fundamental mismatches between measurements and models in aeolian sediment transport prediction: The role of small-scale variability
TL;DR: In this article, the authors argue that improvements in predictions of aeolian sediment transport are limited by incompatibilities between empirical measurements and mathematical models, and they suggest revising model conceptualizations and evaluating the representativeness of steady state saltation to constrain the realism of existing models.
Journal ArticleDOI
The apparent roughness of a sand surface blown by wind from an analytical model of saltation
TL;DR: In this paper, an analytical model of aeolian sand transport is presented, which quantifies the momentum transfer from the wind to the transported sand by providing expressions for the thickness of the saltation layer and the apparent surface roughness.
Journal ArticleDOI
Aeolian particle flux profiles and transport unsteadiness
TL;DR: In this paper, the potential influence of wind unsteadiness and time-varying intensity of transport on the geometry (slope, curvature) of aeolian particle flux profiles is explored.
Journal ArticleDOI
Analytical model for flux saturation in sediment transport.
TL;DR: A theoretical model for sediment transport is presented which accounts for both these relaxation mechanisms and for the different types of sediment entrainment prevailing under different environmental conditions, and derives a closed expression for the saturation length of sediment flux, which can be applied under different physical conditions.
Journal ArticleDOI
Saltation transport on Mars
TL;DR: The first calculation of saltation transport and dune formation on Mars is presented and it is found that the rate at which grains are entrained into saltation onMars is 1 order of magnitude higher than on Earth.
References
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Book
The Physics of Blown Sand and Desert Dunes
TL;DR: The physics of blown sand and desert dunes, The physics of windblown sand and sand dunes, this paper, and the physics of dunes in the Middle East and Africa.
Journal ArticleDOI
The Physics of Blown Sand and Desert Dunes
TL;DR: Bagnold as mentioned in this paper described his travels in the Egyptian and Libyan Deserts, and combined the results of experimental research in a wind tunnel with personal observations in the desert, and the explanations of many desert features vitally affecting such operations will interest a wide range of readers.
Journal ArticleDOI
Saltation of uniform grains in air
TL;DR: In this paper, the interaction between a turbulent wind and the motion of uniform saltating grains of sand or soil, so massive as to fail to enter into suspension, is examined on the basis of two complementary hypotheses.
Journal ArticleDOI
Soil Transport by Winds on Mars
TL;DR: In this paper, a semi-empirical formula is developed for estimating the total amount of surface material moving in eolian saltation, surface traction, and suspension on the surface of Mars, and the ratio of final particle speed to the particle threshold friction speed is found to be several times that of saltation on earth.
Book ChapterDOI
Wind modification and bed response during saltation of sand in air
Robert S. Anderson,Peter K. Haff +1 more
TL;DR: In this article, a model of eolian sediment transport was constructed, which is a special case of sand-sized mineral grains subjected to moderate winds: saltation, and the model consists of four compartments corresponding to aerodynamic entrainment, grain trajectories, grain-bed impacts, and momentum extraction from the wind.