| 湿沙的风蚀起动风速实验研究 |
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| 引用本文： | 刘小平,董治宝.湿沙的风蚀起动风速实验研究[J].水土保持通报,2002,22(2):1-4,61. |
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| 作者姓名： | 刘小平 董治宝 |
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| 作者单位： | 中国科学院,寒区旱区环境与工程研究所,风沙物理与工程实验室,甘肃,兰州,730000 |
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| 基金项目： | 中国科学院"百人计划";国家自然科学基金(40001005) |
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| 摘 要： | 在土壤风蚀研究中 ,Bagnold建立的干沙子的起动风速与沙粒粒径关系的表达式已被广泛接受。然而 ,沙子含水率是影响沙粒起动风速的重要因子 ,因为沙子在湿润状态下 ,水分子与沙粒颗粒之间的拉张力增加了颗粒间的内聚力。通过风洞模拟实验研究了各种粒径的沙子在湿润状态下的起动风速。实验结果表明 ,湿沙的起动摩阻速度与干沙的起动摩阻速度之比——相对起动摩阻速度能更好地反映沙子含水率对起动风速的影响。建立了湿沙子的起动风速与沙粒粒径和沙子含水率的关系式
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| 关 键 词： | 沙子含水率 沙粒粒径 起动风速 |
| 文章编号： | 1000-288X(2002)02-0001-04 |
| 收稿时间： | 2001/12/31 0:00:00 |
Wind Threshold Shear Velocities of Sands at Moistened State |
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| LIU Xiao ping and DONG Zhi bao.Wind Threshold Shear Velocities of Sands at Moistened State[J].Bulletin of Soil and Water Conservation,2002,22(2):1-4,61. |
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| Authors: | LIU Xiao ping and DONG Zhi bao |
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| Institution: | Laboratory of Blown Sand Physics and Desert Environments, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, Gansu Province, China;Laboratory of Blown Sand Physics and Desert Environments, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, Gansu Province, China |
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| Abstract: | The widely accepted Bagnold type function to calculate threshold wind velocity or shear velocity was developed for dry sands. However, surface moisture is an extremely important variable controlling the entrainment process of sands by wind because the tensile force between the water molecules and sand grains produces cohesion. The detailed results from experiments in a laboratory wind tunnel are reported, in which the threshold shear velocities for a range of sand grains with different moisture content are measured. The results show that the functions relating threshold shear velocity and moisture content are different for different sized sands. Relative threshold shear velocity, the ratio of threshold shear velocity of sand at moistened state to that at dry state is better related to moisture content. For given grain size, the threshold shear velocity is proportional to the square root of moisture content. |
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| Keywords: | moisture content particle diameter threshold shear velocity |
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