The discrete element method has been used to study the lift F_L on a stationary disc immersed coaxially in a slowly rotating cylinder containing a granular material. In a tall granular column, F_L rises with the immersion depth h, but reaches a roughly constant asymptote at large h, in agreement with previous studies. Our results indicate that the argument in some earlier studies that F_L is proportional to the static stress gradient is incorrect. Instead, our results show that the lift is caused by an asymmetry in the dilation and shear rate between the regions above and below the disc. We argue that the cause of the lift is similar to that in fluids, namely that it arises as a result of the disturbance in the velocity and density fields around the body due to its motion relative to the granular bed. © 2017 American Institute of Chemical Engineers AIChE J, 2017

中文翻译：

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盘片上的升降机浸没在旋转的颗粒床中

离散单元法已被用于研究同轴地浸没在包含颗粒材料的缓慢旋转的圆柱体中的固定圆盘上的升力F _L。与以前的研究一致，在一个高大的颗粒状圆柱中，F _L随着浸入深度h上升，但在大h时达到大致恒定的渐近线。我们的结果表明，在一些较早的研究中，F _L与静态应力梯度成正比是不正确的。相反，我们的结果表明，升力是由圆盘上方和下方区域之间的膨胀和剪切速率的不对称引起的。我们认为，升力的原因与流体中的原因相似，即它的产生是由于相对于颗粒床的运动引起的人体周围速度和密度场的扰动所致。©2017美国化学工程师学会AIChE J，2017