{"title":"The influences of boundary layer thickness on the characteristics of saltation sand flow – A large eddy simulation study","authors":"ShengJun Feng , Ping Wang","doi":"10.1016/j.aeolia.2023.100853","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper, Large Eddy Simulation (LES) of turbulence and Lagrangian model of sand particle motion are adopted to study the characteristics of wind-blown sand flow for different boundary layer thickness. The simulations are conducted within computational domain height (boundary layer thickness) of <em>δ</em> = 0.5 <em>m</em>, 1 <em>m</em>, 5 <em>m</em> and 12 <em>m</em><span>, respectively. It is found by comparing the computational results that the mass flux and sand transport rate increase with the increase of boundary layer thickness for the same frictional wind velocity, and the fluctuation of particle velocity and sand transport rate increase significantly too. The spatial scales of particle structure, defined by the correlation of sand particle concentration, significantly increase with </span><em>δ</em>, so does the time scale of statistical stability of sand transport rate. For two computational domains of <em>δ</em> = 1 <em>m</em> and 12 <em>m</em>, the statistical relative error of sand transport rate reduce to less than 5 % only when the average time goes higher than 45 <em>δ/U<sub>b</sub></em>, where <em>U<sub>b</sub></em> is the bulk fluid velocity. In the context of turbulence, it might take about 10 mins to obtain reliable sand statistics in the neutral atmospheric boundary layer whose boundary layer thickness is about 100–200 <em>m</em>.</p></div>","PeriodicalId":49246,"journal":{"name":"Aeolian Research","volume":null,"pages":null},"PeriodicalIF":3.1000,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Aeolian Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1875963723000010","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOGRAPHY, PHYSICAL","Score":null,"Total":0}
引用次数: 2
Abstract
In this paper, Large Eddy Simulation (LES) of turbulence and Lagrangian model of sand particle motion are adopted to study the characteristics of wind-blown sand flow for different boundary layer thickness. The simulations are conducted within computational domain height (boundary layer thickness) of δ = 0.5 m, 1 m, 5 m and 12 m, respectively. It is found by comparing the computational results that the mass flux and sand transport rate increase with the increase of boundary layer thickness for the same frictional wind velocity, and the fluctuation of particle velocity and sand transport rate increase significantly too. The spatial scales of particle structure, defined by the correlation of sand particle concentration, significantly increase with δ, so does the time scale of statistical stability of sand transport rate. For two computational domains of δ = 1 m and 12 m, the statistical relative error of sand transport rate reduce to less than 5 % only when the average time goes higher than 45 δ/Ub, where Ub is the bulk fluid velocity. In the context of turbulence, it might take about 10 mins to obtain reliable sand statistics in the neutral atmospheric boundary layer whose boundary layer thickness is about 100–200 m.
期刊介绍:
The scope of Aeolian Research includes the following topics:
• Fundamental Aeolian processes, including sand and dust entrainment, transport and deposition of sediment
• Modeling and field studies of Aeolian processes
• Instrumentation/measurement in the field and lab
• Practical applications including environmental impacts and erosion control
• Aeolian landforms, geomorphology and paleoenvironments
• Dust-atmosphere/cloud interactions.