3D numerical simulation of the evolutionary process of aeolian downsized crescent-shaped dunes

Xiaosi, Zhou; Zhang, Yang; Wang, Yüan; Li, Min

doi:10.1016/j.aeolia.2016.03.001

Cited by 11 publications

(2 citation statements)

References 40 publications

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“…The authors further adjusted the local concentration of sand flow through artificial interventions, including sand supply from upstream and sand bed vibration, to prolong the unsaturated dune evolution process (Y. Zhang et al, 2014bZhang et al, , 2017, and obtained results similar to numerical simulations (Zhou et al, 2016). Sand bed vibration herein induces local weightlessness, so the aerodynamic threshold of entraining sand particles is reduced; coupled with the sand supply located upstream, more sand particles enter the air, the local concentration of sand flow gets increased, and the effect of air flow on small sand piles is no longer intense erosion; instead, the pile is allowed to deform gradually as it migrates downstream.…”

Section: Particle-scale Characteristicsmentioning

confidence: 86%

Local Similarity Between Aeolian Barchan Dunes and Their Downsized Subaqueous Counterparts

Zhang,

Lin,

et al. 2024

JGR Earth Surface

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Aeolian barchan dunes on Earth and other planets have been widely investigated. Much of the understanding of barchan dune morphodynamics comes from field observations, numerical simulations, and downsized water‐tunnel experiments as well. Many of the evolution of barchan dunes in water‐tunnel experiments are similar to those of aeolian cases, although they have notable differences in scale, sand particle motion and hydrodynamic characteristics. Here, we first review the literature on the local similarities between aeolian and downsized subaqueous barchan dunes, focusing on (a) dune formation, (b) dune morphology, (c) particle‐scale characteristics, and (d) sand/dune emission at horns. A comprehensive description of double‐dune interaction modes is then presented to illustrate the local similarity of barchan dune morphodynamics. Specifically, as the interaction mode undergoes a process of “merging‐splitting‐chasing,” the similarity between the interaction modes of aeolian and downsized subaqueous dunes continuously decreases. Furthermore, we summarize the significance and limitations of downsized water‐tunnel experiments for barchan dunes, and highlight the focus for future investigation.

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Section: Particle-scale Characteristicsmentioning

confidence: 86%

Local Similarity Between Aeolian Barchan Dunes and Their Downsized Subaqueous Counterparts

Zhang,

Lin,

et al. 2024

JGR Earth Surface

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“…Some studies have found that the sand content in the wind-sand flow decreases exponentially with the increase of height [10][11][12] . However, some other studies have shown that the sand flux presents a square root decreasing relationship with height 13,14 . The results of the previous studies have been obtained through measured observations, and have not yielded uniform conclusions 15,16 .…”

Section: Numerical Simulation Of Wind Field and Sand Flux In Crescentmentioning

confidence: 88%

Numerical simulation of wind field and sand flux in crescentic sand dunes

Zhang

et al. 2021

Sci Rep

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Sand flux is the key factor to determine the migration of sand dunes and the erosion to the surrounding environment. There are crescent-shaped sand dunes of various scales in the desert, and there are significant differences in spatial wind field and sand flux among them. However, due to the difficulty of monitoring, it is difficult to continuously observe the spatial wind field and sand flux around the larger crescentic dunes. On the basis of the Reynolds-Average Navier–Stokes (RA-NS) equation and the stress and sand flux model, the distribution of wind field and sand flux of a circular dune with a height of 4.2 m and a length of about 100 m during the four evolutionary periods of the evolution into a crescentic dune was simulated in this study. By comparing with the measured results, we verified that the closer to the leeward side, the more the simulated values of the velocity in wind field and sand flux were in line with the measured results. In order to further analyze the influence of the height of dune and other relevant parameters on sand flux, we simulated the influence on wind field and sand flux by changing the air viscosity and wind velocity of upper boundary. We found that the air viscosity mainly affected the amount of deposited sand on the leeward side of sand dune, while the increase of wind velocity would undoubtedly increase the sand flux of the whole sand dune. In addition, the simulation results also showed that the influence of changes in height of dune on the turbulent intensity of leeward side was very significant, and the turbulent intensity increased with the height of dune. The height changes of tall dunes gradually affected the transport of sand caused by wind flow behind the leeward side because that the rotation of the wind flow would form new vortexes at the large pores behind the leeward side, which would increase the turbulent energy in space and thus would increase the distance of migration of the lifting sand. While the low sand dunes could not form extra small vortexes at the bottom of the leeward side, so the wind velocity was small and the eddy currents behind the leeward side were more stable. The simulation results indicated that wind velocity was not the only reason for increasing the amount of sand flux, and the fluctuation of wind flow caused by turbulence could also stimulate the movement of sand particles on the ground.

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Wind dynamic environment and wind-sand erosion and deposition processes on different surfaces along the Dunhuang–Golmud railway, China

Zhang

et al. 2023

J. Arid Land

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3D numerical simulation of the evolutionary process of aeolian downsized crescent-shaped dunes

Cited by 11 publications

References 40 publications

Local Similarity Between Aeolian Barchan Dunes and Their Downsized Subaqueous Counterparts

Local Similarity Between Aeolian Barchan Dunes and Their Downsized Subaqueous Counterparts

Numerical simulation of wind field and sand flux in crescentic sand dunes

Wind dynamic environment and wind-sand erosion and deposition processes on different surfaces along the Dunhuang–Golmud railway, China

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