探头在准二维颗粒介质中慢速运行的受阻实验研究

Slow drag force of cone intruding vertically into a Quasi-two-dimensional granular bed

测量了圆锥探头缓慢压入准二维颗粒介质过程中所受阻力随深度的变化,发现阻力曲线在不同区域呈现不同的增长规律,曲线全过程存在两次增长规律的转变。本实验条件下观测到的现象表明:当填充颗粒总高度较高时,阻力曲线存在两个拐点,前部拐点是由颗粒回填所致,拐点深度约65mm(与探头尺寸有关),且不随颗粒填充高度变化,后部拐点是由于底部边界影响所致;后部拐点出现的深度Z2随着颗粒填充高度Zmax的增加线性增加,容器底部边界开始影响探头受力时探头距离底部的距离H也会随着颗粒填充高度Zmax的增加而增加,Z2-Zmax和H-Zmax关系拟合直线的斜率均约为0.5。

By measuring the slow pushing force of cone intruding vertically into a Quasi-two-dimensional granular bed,depth dependence of vertical drag force in granular medium is studied experimentally.It is found that the drag force follows different laws of depth dependence in different regimes.It is observed that,when the granular bed is high enough,there exist two inflexion on the whole curve.The first inflexion is caused by the backfilling of the granules,its depth is about 65mm(depends on the size of the probe),and does not change with the granule filling height.The second inflexion is caused by the bottom boundary,its depth Z2 increases linearly with the granule filling height Zmax.The distance H between the probe and the bottom increases with the increase of Zmax,too.The Z2-Zmax and H-Zmax curves by data-fitting are represented as straight lines with the same slope of about 0.5.