论文标题
部分可观测时空混沌系统的无模型预测
Transition from granular to Brownian suspension : an inclined plane experiment
论文作者
论文摘要
我们在实验上依次将流动的倾斜颗粒悬浮液的倾斜平面降落，其大小在微米范围内的颗粒，不能忽略热波动。在微型化设置上使用共聚焦显微镜检查，我们观察到，与标准的颗粒流变学相反，流动曲线在很大程度上取决于颗粒的大小。同样，由小颗粒组成的悬浮液在无穷小的倾斜度下流动。从速度测量值中，根据摩擦系数作为无量纲剪切速率（粘性数）以及由热压标准化的粒子压力提取有效的流变学。受到先前的作品的启发[1]，基于描述玻璃转变的热贡献和捕获捕获干扰过渡的无效贡献的现象学模型，这很好地再现了实验观察结果。该模型预测存在低于颗粒状摩擦角的玻璃摩擦角的存在，这是压力施加的流变学框架中玻璃转变的标志。
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.
