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
Uncertainty propagation in aeolian processes: From threshold shear velocity to sand transport rate
TL;DR: In this paper, the uncertainty propagation evident in calculations that use a threshold shear velocity to estimate sand transport rate is investigated, and it is shown that if the wind speed is close to the erosion threshold, every tested model amplifies the variability of the resulting estimated sand transport rates, especially in the case of coarse sand.
Journal ArticleDOI
Two-dimensional airflow modeling underpredicts the wind velocity over dunes
TL;DR: The average turbulent wind field over a barchan dune is investigated by means of Computational Fluid Dynamics and it is found that the fractional speed-up ratio of the wind velocity over the three-dimensional barchans shape differs from the one obtained from two-dimensional calculations of the airflow over the longitudinal cut along the dune's symmetry axis.
Journal ArticleDOI
Dune initiation in a bimodal wind regime
Pauline Delorme,Giles F.S. Wiggs,Matthew C. Baddock,Philippe Claudin,Joanna. M. Nield and,Andrew Valdez +5 more
TL;DR: In this paper, the linear stability theory is used to predict the growth rate and migration velocity of a sand dune field in a bimodal wind regime, and the theoretical predictions compare well with measured dunefield attributes as characterized by high resolution Digital Elevation Models measured using repeat terres trial laser scanning.
Journal ArticleDOI
Numerical modeling of wind-blown sand on Mars
TL;DR: The results show that the “overshoot” phenomenon also exists in the evolution of wind-blown sand on Mars both temporally and spatially; impact entrainment affects the sand transport rate on Mars when the wind speed is smaller or larger than the fluid threshold.
Posted Content
Measurements of the aeolian sand transport saturation length
TL;DR: In this article, the saturation length of a dune is measured in a wind tunnel experiment and linear stability analysis of dune formation is used to deduce the length of the saturation from field data.
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.