欧拉颗粒流模型下的近床面风沙跃移速度分布特征

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.

Velocity Distribution of Aeolian Saltation on Sand Bed Surface by Euler-Granular Model

The velocity of sand particles in aeolian processes is an important content in the study of aeolian physics. In order to reflect the change of the concentration and velocity distribution of sand particles in wind-sand movement, this paper used the two-dimensional Euler-Granular model to simulate the flow process of wind-sand from the perspective of multi-phase flow.The model is verified to be 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 the bed surface is obtained after counting the physical quantity of sand particles.The statistical results show that the volume fraction of sand decreases exponentially with the change of height, and a saturation layer appears near the ground.The volume fraction of saturated sand is 1E-7, which decayed faster above the saturated layer.The velocity distribution of sand phase and probability density function of velocity distribution at different time were calculated by counting the velocity information of sand particle with volume fraction greater than 1E-7.