Boundary-layer turbulence characteristics during aeolian saltation
نویسندگان
چکیده
منابع مشابه
Bursts 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 ...
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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...
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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...
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In previous chapters boundary layers were evident as thin layers across which thermal, dynamic, and material properties of a free interior flow make a transition to their boundary values and/or boundary fluxes. In those cases the thinness of the boundary layer was typically a statement of the smallness of the relevant diffusivity; e.g., the depth h of the laminar Ekman boundary layer scales as ...
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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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ژورنال
عنوان ژورنال: Geophysical Research Letters
سال: 2012
ISSN: 0094-8276
DOI: 10.1029/2012gl052234