【摘要】 通过风洞实验研究了由细沙粒和粗粉粒组成的类土壤颗粒的风力输运过程.实验发现沙粒的质量流量廓线与粉粒的质量流量廓线形式完全不同,在对数-线性坐标中沙粒廓线为直线而粉粒廓线呈3次曲线型.发现粉粒的存在对沙粒的质量流量廓线斜率没有影响,只是改变了沙粒的总输沙率.根据粉粒对沙粒输运特性影响的不同,粉粒质量分数存在一临界值,对于本实验中所用材料此临界值为15%.在低于此临界值时,输沙率随粉粒的质量分数的增大而增大;当高于此临界值后,输沙率随粉粒的质量分数的增大而减小.实验中沙波纹的高度和波长随风速及粉粒的质量分数的增大而增大,而当粉粒的质量分数超过15%时沙波纹消失.更多还原

【Abstract】 Aeolian grain transport on the soil-like surface composed of fine sand and silt is measured in a wind tunnel.It is found that the form of mass flux profile of sand is different from that of silt.Mass flux profile of sand is a straight line in log-linear plot but mass flux profile of silt is more like a third power curve,and the silt fraction in the soillike surface has slight effect on the slope of sand mass flux profile but affects the amount of total sand transport rate.According to the effect of silt on the motion of sand grains,a critical silt mass fraction in the surface layer is revealed.For the grain material during this experiment,the critical value approaches 15%.When the silt mass fraction is below the critical value,sand transport rate increases with silt mass fraction.However,when the silt mass fraction is beyond the level,sand transport rate decreases with silt fraction.And the sand ripples on the surface arise obviously with the increasing silt mass fraction and wind speed,but disappear as silt mass fraction exceeds 15%.更多还原