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arXiv 2105.01351cond-mat.softcond-mat.other
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环形剪切池中密度驱动偏析的实验研究和数值模拟

Experimental investigation and numerical modelling of density-driven segregation in an annular shear cell

Monica Tirapelle, Andrea Santomaso, Patrick Richard, Riccardo Artoni

摘要:

由于颗粒大小、形状、密度和流动特性的差异,颗粒材料会自发分离。在本文中,我们实验研究密度差驱动的偏析范围内的密度比和重粒子浓度。实验是在一个环形剪切池中进行的,该剪切池具有旋转的凹凸不平的底部,产生指数剪切剖面。该单元最初填充有一层轻颗粒和上层较重的颗粒,并且在顶部,负载提供限制。分离过程通过透明侧壁用相机拍摄,并通过后处理图像分析评估颗粒浓度在空间和时间上的演变。我们还提出了一个连续的方法来模拟密度驱动的隔离。我们使用一个隔离扩散传输方程,有效粘度和摩擦系数的本构关系,和一个类似于斯托克斯定律的隔离速度。通过与实验结果的比较,验证了该模型,可以成功地预测密度驱动的偏析在不同的密度比和体积分数。

英文摘要:

Granular materials segregate spontaneously due to differences in particle size, shape, density and flow behaviour. In this paper we experimentally investigate density-difference-driven segregation for a range of density ratios and a range of heavy particle concentrations. The experiments are conducted in an annular shear cell with rotating bumpy bottom that yields an exponential shear profile. The cell is initially filled with a layer of light particles and an upper layer of heavier grains and, on top, a load provides confinement. The segregation process is filmed through the transparent side-wall with a camera, and the evolution of particle concentration in space and time is evaluated by means of post-processing image analysis. We also propose a continuum-approach to model density-driven segregation. We use a segregation-diffusion transport equation, constitutive relations for effective viscosity and friction coefficient, and a segregation velocity analogous to the Stokes' law. The model, which is validated by comparison with experimental findings, can successfully predict density-driven segregation at different density ratios and volumetric fraction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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