沙粒起动风速的影响因素研究  

Factors Influencing Threshold Wind Velocity of Sand Particles

作　　者：武建军[1] 孙焕青[1] 何丽红[1] 

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室、土木工程与力学学院,甘肃兰州730000

出　　处：《中国沙漠》2010年第4期743-748,共6页Journal of Desert Research

基　　金：国家自然科学基金项目(10772075,10772074);国家自然科学基金重点项目(10532040)资助;国家重点基础研究发展计划项目(2009CB421304)

摘　　要：通过对风场中沙床表面沙粒的受力分析,建立了坡面沙粒起动风速的理论公式,并将计算结果与已有实验研究结果进行了比较,结果表明,给出的理论计算公式是正确的。在此基础上,详细讨论了坡角、风向角、荷质比、电场力以及空气上升力对坡面沙粒起动风速的影响。其结果是:坡角一定时,沙粒的起动风速随风向角的增大而增大;风向一定时,背风坡沙粒的起动风速随坡角的增大而变小;弱电场中电场力对沙粒起动风速几乎没有影响,强电场中随着沙粒荷质比的增大,起动风速明显减小;空气上升力明显使沙粒起动风速减小。A theoretical formula for computing the threshold wind velocity of sands over slopes is derived based on analysis of the forces acting on the particles on sand bed in wind-field. This formula is proved to be feasible through comparison between the calculated threshold wind velocities and the experimental measurements. Besides, the effects of some influencing factors--including slope angle, wind direction angle, charge-to-mass ratio of particles, electrostatic force and aerodynamic lift--to sand particle＇s threshold wind velocity are discussed in detail. It is disclosed that the threshold wind velocity increases with the increment of the wind direction angle at the same slope angle; it decreases with the increment of the slope angle in leeward slope at the same wind direction; the electrostatic force in a weak electric field makes no difference to the threshold velocity; the threshold wind velocity decreases significantly with the increment of the chargeto-mass ratio in a strong electric field; it also decreases obviously under function of the aerodynamic lift.

关 键 词：起动风速 坡角 风向角 空气上升力 电场力 

分 类 号：X169[环境科学与工程—环境科学]