High-frequency measurements of aeolian saltation flux: Field-based methodology and applications
نویسندگان
چکیده
منابع مشابه
Wind-invariant saltation heights imply linear scaling of aeolian saltation flux with shear stress
Wind-driven sand transport generates atmospheric dust, forms dunes, and sculpts landscapes. However, it remains unclear how the flux of particles in aeolian saltation-the wind-driven transport of sand in hopping trajectories-scales with wind speed, largely because models do not agree on how particle speeds and trajectories change with wind shear velocity. We present comprehensive measurements, ...
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We reveal that the transition in the saturated flux for aeolian saltation is generically discontinuous by explicitly simulating particle motion in turbulent flow in two dimensions. The discontinuity is followed by a coexistence interval with two metastable solutions. We found also that the mere presence of mid-air collisions, surprisingly, enhances the saturated flux, which has a peak for an in...
متن کاملBursts in discontinuous Aeolian saltation
Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of discontinuous flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the fluid threshold Shields number θc. The time delay between each burst decreases on average with the increase ...
متن کاملDynamics of particles in aeolian saltation
In aeolian transport saltation is an important link by which momentum is transmitted from the air to the bed through grain impact, but momentum transfer, impact and subsequent entrainment take place in a very shallow layer at the air-bed interface with large velocity gradients. Consequently, experimental evidence on the impact-entrainment processes has been obtained from few and simplified stud...
متن کاملThe vertical variation of particle speed and flux density in aeolian saltation: measurement and modeling
Particle dynamics in aeolian saltation has been studied in a boundary layer wind tunnel above beds composed of quartz grains having diameters of either 254 μm or 320 μm. The cross section of the tunnel is 600 mm × 900 mm and its thick boundary layer allows precise estimation of the fluid friction speed. Saltation is modelled using a numerical saltation model and predicted grain speeds agree fai...
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ژورنال
عنوان ژورنال: Aeolian Research
سال: 2018
ISSN: 1875-9637
DOI: 10.1016/j.aeolia.2017.12.003