摘要
针对目前土壤风蚀中土壤颗粒释放过程机理研究存在的不足,建立了颗粒在土壤表面起动、滚动、起跳的土壤颗粒释放力学模型,同时考虑了太阳辐射及地表温度产生的向上垂向风速对颗粒起动风速的影响,并采用前人的实验结果与本文模型数值计算结果进行了对比分析,证明其模型的合理性。数值结果表明:起动风速随颗粒粒径的增大先减小后增大,其中在0.12～0.14 mm粒径范围内颗粒最容易起动,同时床面温度越高对颗粒的起动风速影响也越明显,同一粒径下床面温度越高起动风速越小。颗粒在床面上的运动不是纯滚动,而是滚动中有滑动。颗粒起跳速度主要分布在0.3～0.65 m/s之间;起跳角度30°～35°之间;颗粒起跳的角速度主要分布在600～1 200 rev/s。土壤颗粒释放微观过程的研究将对改进土壤风蚀输送过程中的宏观监测与预报起到重要作用。
Soil particles release is a key influencing factor in soil wind erosion,but the study of release mechanism is lack and insufficient.In order to describe the vertical field which is engendered by temperature effect of earth surface,the basic soil particles release model of starting-up,rolling motion and saltation of soil particles is established in this paper.At the same time,the numerical calculation results of the model are good agreement with predecessors＇ experimental results,which indicates the model of this paper is appropriate.And the numerical simulation results of this paper show that with the particle diameter enlarging the threshold wind velocity weakens and then enlarges,and when the particle diameter is between 0.12 mm and 0.14 mm,the particle is the easier to start up.At the meantime,the higher the bed temperature is,the weaker the particles＇ threshold wind velocity is.When the wind velocity is bigger than the threshold wind velocity,the particles begin to start up,they slide and at the time roll on the bed,the velocity of sliding and rolling gradually increases with the rolling distance increasing.When the rolling particles impact the other particle on the bed,they will lift-off,and the lifting-off velocity is between 0.3 m/s and 0.65 m/s（including vertical and horizontal lifting-off velocity）;the lifting-off angle is between 30°and 35°;the lifting-off angular velocity is between 600 rev/s and 1 200 rev/s,which is good agreement with the experimental results of 100-1 000 rev/s and 300-900 rev/s.And based on it,the laws are given about releasing mechanism of soil particles,which is very important to improve the macro-monitoring and forecasting in soil wind erosion.
出处
《干旱区地理》
CSCD
北大核心
2012年第2期248-253,共6页
Arid Land Geography
基金
河南省重点学科资助项目(509919)
河南省教育厅自然科学研究计划项目(2001B130001)
关键词
起动风速
颗粒滚动
碰撞
起跳
threshold wind velocity
soil particle rolling
collision
lift-off
作者简介
岳高伟（1977-），男，河南临颍人，副教授，博士，主要从事环境力学和土壤风蚀研究．Email：yuegaowei@hpu．edu．cn
