| Experimental analysis of sand particles＇ lift-off and incident velocities in wind-blown sand flux |
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| 摘 要： |
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| 关 键 词： | 实验分析 沙微粒 入射速率 提升速率 可能性概率 环境空气动力学 |
Experimental analysis of sand particles' lift-off and incident velocities in wind-blown sand flux |
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| Authors: | Li Xie Zhibao Dong Xiaojing Zheng |
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| Institution: | [1]Key Laboratory of Mechanics on Western Disaster and Environment,Ministry of Education,Department of Mechanics, Lanzhou University,Lanzhou, Gansu 730000, China [2]Laboratory of Blown Sand Physics and Desert Environments,Cold and Arid Regions Environment and EngineeringResearch Institute, Chinese Academy of Sciences,Lanzhou, Gansu 730000, China |
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| Abstract: | The probability distributions of sand particles' lift-off and incident velocities in a wind-blown sand flux play very important roles in the simulation of the wind-blown sand movement. In this paper, the vertical and the horizontal speeds of sand particles located at 1.0 mm above a sand-bed in a wind-blown sand flux are observed with the aid of Phase Doppler Anemometry (PDA) in a wind tunnel. Based on the experimental data, the probability distributions of not only the vertical lift-off speed but also the lift-off velocity as well as its horizontal component and the incident velocity as well as its vertical and horizontal components can be obtained by the equal distance histogram method. It is found, according to the results of the χ 2-test for these probability distributions, that the probability density functions (pdf's) of the sand particles' lift-off and incident velocities as well as their vertical components are described by the Gamma density function with different peak values and shapes and the downwind incident and lift-off horizontal speeds, respectively, can be described by the lognormal and the Gamma density functions. These pdf's depend on not only the sand particle diameter but also the wind speed. |
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