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11:51
Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
Particle velocity distribution in saltation transport
T D Ho1, P Dupont, A Ould El Moctar
1Institut de Physique de Rennes, CNRS UMR 6251, Université de Rennes 1, 35042 Rennes cedex, France.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 26, 2012
Summary
Particle velocity distributions in wind-driven sand transport are not always Gaussian. Over erodible surfaces, a lognormal distribution indicates the splash process significantly impacts particle movement, unlike on rigid surfaces.
Area of Science:
- Geophysics
- Fluid Dynamics
- Granular Physics
Background:
- Aeolian transport, the movement of particles by wind, is a fundamental geomorphic process.
- Understanding particle velocity distributions is key to modeling sediment transport dynamics.
Purpose of the Study:
- To investigate particle velocity distributions during aeolian saltation.
- To determine the influence of the bed surface type on these distributions.
- To elucidate the role of the splash process in non-Gaussian velocity statistics.
Main Methods:
- Wind-tunnel experiments were conducted to measure particle velocities.
- Extended statistical analysis was applied to the velocity data.
- Comparisons were made between saltation over erodible and rigid beds.
Main Results:
- Vertical lift-off velocity distributions over erodible beds significantly deviate from Gaussian, showing a lognormal tail.
- Saltation over rigid beds resulted in Gaussian velocity distributions.
- The splash process, unique to erodible beds, was identified as the cause of non-Gaussian statistics.
Conclusions:
- The splash process fundamentally alters particle velocity distributions in aeolian saltation.
- Lognormal velocity distributions are linked to the energy propagation and fragmentation analog within granular beds.
- These findings highlight the critical importance of splash dynamics in aeolian transport models.
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