Representation model of wind velocity fluctuations and saltation transport in aeolian sand flow

Zheng, Xiaojing; Bo, Tian Li

doi:10.1016/j.jweia.2021.104846

Cited by 12 publications

(7 citation statements)

References 57 publications

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“…Through this process, the information of all eroded SBEs in T n is determined. Subsequently, an eroded SBE is randomly selected, and the "predictive model for aeolian sand transport considering the influence of turbulence" proposed by Zheng and Bo (2022) is used to calculate the turbulent sand flow statistics at that eroded SBE based on the actual local friction velocity and the sand bed particle diameter. It includes primarily the average per unit width sand transport rate .…”

Section: The Synthetic Overview Of Model Behaviorsmentioning

confidence: 99%

“…Finally, the quantitative simulation of the formation and evolution of dune fields is completed by iteratively calculating the erosion and transport of SBEs (Zheng, 2009; Zheng et al., 2009). The present work introduced the “predictive model for aeolian sand transport considering the influence of turbulence” proposed by Zheng and Bo (2022) into the CSCDUNE model, and realized the quantitative evolution simulation of dune fields considering turbulence, which makes the dune field simulation more consistent with the natural aeolian sand movement features.…”

Section: Numerical Modelsmentioning

confidence: 99%

“…Through this process, the information of all eroded SBEs in T n is determined. Subsequently, an eroded SBE is randomly selected, and the “predictive model for aeolian sand transport considering the influence of turbulence” proposed by Zheng and Bo (2022) is used to calculate the turbulent sand flow statistics at that eroded SBE based on the actual local friction velocity and the sand bed particle diameter. It includes primarily the average per unit width sand transport rate

{\overline{q}}_{ij}^{n}

, the average saltation length

{\overline{l}}_{ij}^{n}

and the saltation time

{\overline{t}}_{ij}^{n}

of the sand particles, and the average impact velocity of the sand particles on the sand bed

{\overline{{v}_{im}}}_{ij}^{n}

(See A3 in Appendix A for details).This step corresponds to the first trans‐scale process in our model, which is to obtain the characteristic statistics of turbulent sand flow from the motion behavior of discrete sand particles. Calculating the thickness of the eroded SBE according to the statistics of the turbulent sand flow.…”

Section: Numerical Modelsmentioning

confidence: 99%

“…Comprehensive consideration of the relationship between local topography, wind velocity, and sand transport process is critical to the quantitative assessment of dunes, which helps to achieve more realistic discrete element simulations of dune fields (Kok et al, 2012;Zheng, 2009). Differently, in order to more realistically simulate the evolution process of aeolian dune fields under the effect of the atmospheric surface layer (ASL) turbulent wind field, the present work employs the CSCDUNE model considering turbulence, in which the "predictive model for aeolian sand transport considering the influence of turbulence" proposed by Zheng and Bo (2022) is used to simulate the turbulent sand flow with consideration of ASL turbulent fluctuation at an eroded SBE. A brief description of the aeolian sand transport model is as follows.…”

Section: A3 Main Formula Introduction and Accuracy Verification Of Tu...mentioning

confidence: 99%

“…where u τ is the friction velocity; z * represents the aerodynamic roughness height; z is the local height, and k denotes the Karman constant. u′ and w′ are the streamwise and vertical velocity fluctuations of the sand-laden ASL wind field at the location of sand particles, respectively (Zheng & Bo, 2022). The calculation formulas are:…”

Section: A3 Main Formula Introduction and Accuracy Verification Of Tu...mentioning

confidence: 99%

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Temporal Evolution of Dune Number Density in a Barchan Dune Field

2023

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The present work examines the temporal evolution of dune number density in desert barchan dune fields and the effects of wind velocity, particle diameter and sand supply thickness using the Comprehensive Scale‐Coupled Model of dune field considering turbulence. Results show that the dune number density exhibits a temporal evolution trend of “increase—decrease—tend to be stable,” which is similar to the “overshoot” phenomenon of the per unit width sand transport rate evolving with time. The larger the wind velocity and the smaller the particle diameter are, the enhanced surface sand transport by wind causes the dune number density peak to be larger and appear earlier, but the more active dune interactions result in a higher decay rate during the decline stage. In addition, a small sand supply thickness slows sand accumulation and thus delays the initial development of barchans. With an increase in the sand supply thickness, more small‐scale barchans are formed earlier in dune fields due to gradually sufficient sand amounts, which promotes dune interactions and thus accelerates the decay of dune number density. Nevertheless, as the sand supply thickness continuously increases, the barchans link together to form dune chains, resulting in a slowed migration velocity and a reduced spatial density of interactions. The present work makes up for the lack of understanding of the initial evolution stage of barchan dune fields and the dune interactions in existing studies, and thus may be helpful for gaining insight into the dynamic evolution process of aeolian dune systems.

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Section: The Synthetic Overview Of Model Behaviorsmentioning

confidence: 99%