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以公切角表征床-沙位置关系的非均匀沙起动风速

发表时间:2009-08-31  浏览量:1515  下载量:717
全部作者: 潘喜英,李晖,黄宁
作者单位: 兰州大学西部灾害与环境力学教育部重点实验室
摘 要: 以起动沙粒和上风向沙粒的内公切线与风速风向的交角表征上风向沙粒的遮拦作用,以起动沙粒和下风向沙粒的内公切线与风速风向的交角表征下风向沙粒的阻拦作用。引入这2个参数表征床面颗粒对起动沙粒的荫暴作用,并对起动沙粒进行受力分析,给出起动的初始条件,即力矩平衡方程,从而确定非均匀沙起动沙粒的粒径与起动自由风速之间的关系。根据实验数据得到均匀沙公式中的回归系数,并运用非均匀沙起动沙粒的粒径与起动自由风速的关系式计算出各个粒级所对应的起动风速,其数值计算结果与实验结果的相关系数为0.941 1,从而证明了模型的合理性。
关 键 词: 水土保持学;公切角;起动风速;非均匀沙;荫暴作用
Title: Threshold wind velocity of non-uniform sand with bed-sand position relationship expressed by common tangential angle
Author: PAN Xiying, LI Hui, HUANG Ning
Organization: Key Laboratory of Mechanics on Western Disaster and Environment of Ministry of Education, Lanzhou University
Abstract: This paper takes the angles between the internal common tangents of initiating particle to its windward sand particles and wind speed and direction as parameters to present shielding effect of windward sand particles and takes the angles between the internal common tangents of initiating particle to its leeward sand particles and wind speed and direction as parameters to present intercepting effects of leeward sand particles. The paper also introduces these two parameters to present hiding-exposing action of bed particle to initiating particle. Then force analysis of initiating particle is carried out, and the initial conditions for starting are given, the expression which gives the relation between wind velocity and initiating particle diameters of non-uniform sand is determined. Then, according to the coefficients determined by experimental data, the threshold wind velocity of each size fraction is calculated. The correlative coefficient between the calculated results and the experimental data is 0.941 1, which suggests that the calculation model in this paper is reasonable.
Key words: soil and water conservation; common tangential angle; threshold wind velocity; non-uniform sand; hiding-exposing action
发表期数: 2009年8月第16期
引用格式: 潘喜英,李晖,黄宁. 以公切角表征床-沙位置关系的非均匀沙起动风速[J]. 中国科技论文在线精品论文,2009,2(16):1633-1638.
 
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