arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2209.13239cond-mat.softphysics.class-ph
收藏

从颗粒状到布朗悬浮体的转变:斜面实验

Transition from granular to Brownian suspension : an inclined plane experiment

Alice Billon, Yoël Forterre, Olivier Pouliquen, Olivier Dauchot

AI总结:

本研究通过斜面实验观测微米级颗粒悬浮体流动,发现流动依赖颗粒尺寸,并建立融合热与无热贡献的模型,预测玻璃态摩擦角,揭示玻璃化转变特征。

摘要:

我们通过实验重新研究了密集颗粒悬浮体在斜面上的流动,其中颗粒尺寸在微米范围内,此时热涨落不可忽略。利用小型化装置上的共聚焦显微镜,我们观察到,与标准颗粒流变学相反,流动剖面强烈依赖于颗粒尺寸。此外,由足够小颗粒组成的悬浮体在极小倾角下即可流动。根据速度测量,我们提取了有效流变学,以摩擦系数作为无量纲剪切速率(粘性数)和颗粒压力(以热压力归一化)的函数。受先前工作[1]的启发,我们发展了一个现象学模型,该模型基于描述玻璃化转变的热贡献与描述堵塞转变的无热贡献之和,能够很好地再现实验观测结果。该模型预测存在一个低于颗粒无热摩擦角的玻璃态摩擦角,这是在压力施加流变学框架下玻璃化转变的一个特征。

英文摘要:

We experimentally revisite the flow down an inclined plane of dense granular suspensions, with particles of sizes in the micron range, for which thermal fluctuations cannot be ignored. Using confocal microscopy on a miniaturized set-up, we observe that, in contrast with standard granular rheology, the flow profiles strongly depend on the particles size. Also, suspensions composed of small enough particles flow at infinitesimal inclinations. From the velocity measurements, an effective rheology is extracted in terms of a friction coefficient as a fonction of the dimensionless shear rate (the viscous number), and of the particle pressure normalized by the thermal pressure. Inspired by a previous work [1], a phenomenological model based on the sum of a thermal contribution describing the glass transition and an athermal contribution capturing the jamming transition is developed, which reproduces well the experimental observations. The model predicts the existence of a glassy friction angle lower than the granular athermal friction angle, a signature of the glass transition in the framework of a pressure imposed rheology.

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。

↑