论文标题
剪切下非凸粒颗粒的合奏中的次级流
Secondary flow in ensembles of non-convex granular particles under shear
论文作者
论文摘要
理论和实验性的颗粒材料的研究通常仅限于凸形晶粒形状。我们证明，非凸线晶粒形状可以导致定性新颖的宏观动力学。空间交叉（六脚架）连续剪切在分裂的容器中。因此，它们会形成一个二级流曲线，该流程与相同几何形状中的杆状或小扁豆形凸晶粒完全相反。表面的十字迁移到旋转中心并下沉，模仿了“反向魏森伯格效应”。观察到的表面流场表明存在颗粒床深度的径向向外流，从而形成对流池。该流场与旋转中心形成的凹痕相连。该效果在很大程度上取决于粒子几何形状和颗粒床的高度。
Studies of granular materials, both theoretical and experimental, are often restricted to convex grain shapes. We demonstrate that a non-convex grain shape can lead to a qualitatively novel macroscopic dynamics. Spatial crosses (hexapods) are continuously sheared in a split-bottom container. Thereby, they develop a secondary flow profile that is completely opposite to that of rod-shaped or lentil-shaped convex grains in the same geometry. The crosses at the surface migrate towards the rotation center and sink there, mimicking a `reverse Weissenberg effect'. The observed surface flow field suggests the existence of a radial outward flow in the depth of the granular bed, thus forming a convection cell. This flow field is connected with a dimple formed in the rotation center. The effect is strongly dependent on the particle geometry and the height of the granular bed.
