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Related papers: Bursts in discontinuous Aeolian saltation

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Wind-blown sand and dust models depend sensitively on the threshold wind stress. However, laboratory and numerical experiments suggest the coexistence of distinct "fluid" and "impact" thresholds for the initiation and cessation of aeolian…

Geophysics · Physics 2017-08-01 Raleigh L. Martin , Jasper F. Kok

We reveal a discontinuous transition in the saturated flux for aeolian saltation by simulating explicitly particle motion in turbulent flow. The discontinuity is followed by a coexistence interval with two metastable solutions. The…

Computational Physics · Physics 2015-08-19 M. V. Carneiro , T. Pähtz , H. J. Herrmann

Aeolian transport of sand and dust is driven by turbulent winds that fluctuate over a broad range of temporal and spatial scales. However, commonly used aeolian transport models do not explicitly account for such fluctuations, likely…

Wind-driven sand transport generates atmospheric dust, forms dunes, and sculpts landscapes. However, it remains unclear how the sand flux scales with wind speed, largely because models do not agree on how particle speed changes with wind…

Geophysics · Physics 2017-03-10 Raleigh L. Martin , Jasper F. Kok

Here we compare two extreme regimes of non-suspended fluid-mediated particle transport, transport in light and heavy fluids ("saltation" and "bedload", respectively), regarding their particle fluctuation energy balance. From direct…

Fluid Dynamics · Physics 2015-01-19 Thomas Pähtz , Orencio Durán , Tuan-Duc Ho , Alexandre Valance , Jasper F. Kok

We derive a phenomenological continuum saltation model for aeolian sand transport that can serve as an efficient tool for geomorphological applications. The coupled differential equations for the average density and velocity of sand in the…

Materials Science · Physics 2009-11-07 G. Sauermann , K. Kroy , H. J. Herrmann

Using particle-scale simulations of non-suspended sediment transport for a large range of Newtonian fluids driving transport, including air and water, we determine the bulk transport cessation threshold $\Theta^r_t$ by extrapolating the…

Atmospheric and Oceanic Physics · Physics 2019-09-17 Thomas Pähtz , Orencio Durán

Reliably predicting the geomorphology and climate of planetary bodies requires knowledge of the dynamic threshold wind shear velocity below which saltation transport ceases. Here we measure this threshold in a wind tunnel for four…

Geophysics · Physics 2019-10-28 Wei Zhu , Xinghui Huo , Jie Zhang , Peng Wang , Thomas Pähtz , Ning Huang , Zhiguo He

We investigate the airborne transport of particles on a granular surface by the saltation mechanism through numerical simulation of particle motion coupled with turbulent flow. We determine the saturated flux $q_{s}$ and show that its…

Soft Condensed Matter · Physics 2009-11-11 M. P. Almeida , J. S. Andrade , H. J. Herrmann

Martin and Kok (2018a) measured two distinct aeolian saltation transport thresholds: a larger threshold below which continuous saltation transport becomes intermittent and a smaller threshold below which intermittent saltation transport…

Atmospheric and Oceanic Physics · Physics 2019-01-16 Thomas Pähtz

Aeolian sediment transport is observed to occur on Mars as well as other extraterrestrial environments, generating ripples and dunes as on Earth. The search for terrestrial analogues of planetary bedforms, as well as environmental…

Geophysics · Physics 2021-04-13 B. Andreotti , P. Claudin , J. J. Iversen , J. P. Merrison , K. R. Rasmussen

Saltation threshold, the minimum wind speed for sediment transport, is a fundamental parameter in aeolian processes. The presence of liquid, such as water on Earth or methane on Titan, may affect the threshold values to a great extent.…

Earth and Planetary Astrophysics · Physics 2017-10-18 Xinting Yu , Sarah M. Hörst , Chao He , Nathan T. Bridges , Devon M. Burr , Joshua A. Sebree , James K. Smith

Wind tunnel measurements of the mean saltation length $L$ and of different proxies of the mean saltation height $H$ in saturated aeolian sand transport indicate that $L$ and $H$ are relatively insensitive to both the wind speed and grain…

Fluid Dynamics · Physics 2021-08-16 Thomas Pähtz , Katharina Tholen

We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from $10^{-5} \hspace{0.5 ex} \mathrm{m}$ to $10 \hspace{0.5 ex} \mathrm{m}$ above the…

Geophysics · Physics 2017-04-26 Hirofumi Niiya , Kouichi Nishimura

The wind-driven hopping motion of sand grains, known as saltation, forms dunes and ripples and ejects fine dust particles into the atmosphere on both Earth and Mars. While the wind speed at which saltation is initiated, the fluid threshold,…

Earth and Planetary Astrophysics · Physics 2010-01-28 Jasper F. Kok

Starting from the physics on the grain scale, we develop a simple continuum description of aeolian sand transport. Beyond popular mean-field models, but without sacrificing their computational efficiency, it accounts for both dominant grain…

Soft Condensed Matter · Physics 2012-09-27 Marc Lämmel , Daniel Rings , Klaus Kroy

A surprising feature of flow in slowly sheared model foam (bubble raft) is a measured discontinuity in the rate of strain as a function of position such that part of the system is ``flowing'' and the rest is undergoing ``elastic''…

Soft Condensed Matter · Physics 2007-05-23 Michael Dennin

We scrutinize the temporally-resolved speed of active cargo transport in living cells, and show intermittent bursting motions. These nonlinear fluctuations follow a scaling law over several decades of time and space, the statistical…

Subcellular Processes · Quantitative Biology 2015-06-16 Bo Wang , James Kuo , Steve Granick

The impact of turbulent fluctuations on the forces exerted by a fluid on a towed spherical particle is investigated by means of high-resolution direct numerical simulations. The measurements are carried out using a novel scheme to integrate…

Fluid Dynamics · Physics 2016-11-21 Holger Homann , Jérémie Bec , Rainer Grauer

Wind-blown sand, or "saltation", ejects dust aerosols into the atmosphere, creates sand dunes, and erodes geological features. We present a comprehensive numerical model of steady-state saltation that, in contrast to most previous studies,…

Fluid Dynamics · Physics 2009-01-05 Jasper F. Kok , Nilton O. Renno
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