【摘要】 风沙运动中沙粒速度是风沙物理学研究的重要内容,为反映风沙流运动中沙粒相浓度变化及沙粒的速度分布,从多相流的角度出发,运用二维欧拉颗粒两相流模型对风沙的流动过程进行模拟。通过对比实验中沙粒的体积浓度随高度的变化,验证了模型的准确性,并在此基础上对沙相的运动信息进行统计分析,得到近床面风沙流的沙相速度分布。统计结果表明:在风沙跃移过程中,沙粒体积分数随高度的变化呈指数衰减,并在近地面附近出现浓度饱和层,饱和层沙粒体积分数的数量级为10^-7,且在饱和层上方浓度衰减加快。通过对体积分数大于等于10^-7的沙粒速度信息进行统计,得到不同时刻沙相速度分布,并给出相应的速度分布概率密度函数。更多还原

【Abstract】 The velocity of sand particles in aeolian processes is an important issue in aeolian physics. To reveal the changes in concentration and velocity distribution of sand particles in wind-sand movement, the two-dimensional Euler-Granular model was used to simulate the flow process of wind-sand from the perspective of multi-phase flow. The model was proved accurate by comparing the volume concentration of sand particles with the change of height in the experiment, and the velocity distribution of wind-drift sand near bed surface was obtained by counting the physical quantity of sand particles. The statistical results show that the volume fraction of sand decrease exponentially with the height, and a saturation layer appeare near the ground surface. The volume fraction of saturated sand is in the magnitude of 10^-7, and attenuate fast above the saturated layer. Based on the statistics of the velocity information of sand particles whose volume fraction is greater than or equal to 10^-7, the velocity distribution of sand phase at different times is obtained, and the corresponding probability density function of velocity distribution is given.更多还原