Sand particle dislodgement in windblown sand  

作　　者：Tian-Li Bo Zheng Li Xiao-Jing Zheng 

机构地区：[1]Key Laboratory of Mechanics on Western Disaster and Environment, Lanzhou University [2]Department of Mechanics,Lanzhou University [3]School of Electronical and Machanical Engineering,Xidian University

出　　处：《Acta Mechanica Sinica》2014年第6期910-916,共7页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(11072097,11232006,11202088,10972164,and11121202);the Science Foundation of Ministry of Education of China(308022);Science and technology project of Gansu Province(1208RJYA006);National Key Technology R&D Program(2013BAC07B01)

摘　　要：The incipient motion of sand particle from sand bed plays a very important role in the prediction of windblown sand.In this paper,we proposed a new method for predicting the incipient motion of sand particle based on wind speed fluctuation as follows,when the wind speed is larger than the critical wind speed,if the total impulse on sand particle is larger than the critical impulse,incipient motion of sand particle would take place,otherwise if not.Furthermore,from the analysis of entrainment in the rolling and lifting modes,we come to the following conclusion.When the average wind speed is smaller than the critical wind speed,if the average wind speed is used to judge the incipient motion of sand particle,one will underestimate the number of sand particles jumping from the bed,if the instantaneous wind speed is used to judge incipient motion of sand particle,one will overestimate the number of sand particles jumping from the bed;When the average wind speed is larger than the critical wind speed,either the average or the instantaneous wind speeds is used to judge the incipientmotion of sand particles,one will overestimate the number of sand particles jumping from the bed.The incipient motion of sand particle from sand bed plays a very important role in the prediction of windblown sand.In this paper,we proposed a new method for predicting the incipient motion of sand particle based on wind speed fluctuation as follows,when the wind speed is larger than the critical wind speed,if the total impulse on sand particle is larger than the critical impulse,incipient motion of sand particle would take place,otherwise if not.Furthermore,from the analysis of entrainment in the rolling and lifting modes,we come to the following conclusion.When the average wind speed is smaller than the critical wind speed,if the average wind speed is used to judge the incipient motion of sand particle,one will underestimate the number of sand particles jumping from the bed,if the instantaneous wind speed is used to judge incipient motion of sand particle,one will overestimate the number of sand particles jumping from the bed;When the average wind speed is larger than the critical wind speed,either the average or the instantaneous wind speeds is used to judge the incipientmotion of sand particles,one will overestimate the number of sand particles jumping from the bed.

关 键 词：Incipient motion Rolling mode Average wind speed Total impulse Windblown sand 

分 类 号：O35[理学—流体力学]