论文标题
通过边界条件在密集的颗粒流中控制流变学
Controlling rheology via boundary conditions in dense granular flows
论文作者
论文摘要
边界形状，尤其是粗糙度，强烈控制着密集的颗粒流中的壁滑动量。在本文中，我们旨在量化和理解密集颗粒流的哪些方面受边界条件的控制，并将这些观测值纳入表征慢粒流量的合作非本地模型中。为了检查边界特性的影响，我们在带有旋转内壁和固定外壁的准2D环形剪切电池上执行实验。后来是从具有各种粗糙度，局部凹和合规性的6个墙壁中选择的。我们发现，我们可以使用一组经验确定的模型参数成功捕获全流量，仅通过直接观察设置壁滑速。通过使用光弹性颗粒，我们观察到内部应力如何在粗糙的边界，对应于下壁滑动的情况下更多地波动，并将这种观察结果与源自壁的非局部效应的传播联系起来。
Boundary shape, particularly roughness, strongly controls the amount of wall slip in dense granular flows. In this paper, we aim to quantify and understand which aspects of a dense granular flow are controlled by the boundary condition, and to incorporate these observations into a cooperative nonlocal model characterizing slow granular flows. To examine the influence of boundary properties, we perform experiments on a quasi-2D annular shear cell with a rotating inner wall and a fixed outer wall; the later is selected from among 6 walls with various roughness, local concavity, and compliance. We find that we can successfully capture the full flow profile using a single set of empirically determined model parameters, with only the wall slip velocity set by direct observation. Through the use of photoelastic particles, we observe how the internal stresses fluctuate more for rougher boundaries, corresponding to lower wall slip, and connect this observation to the propagation of nonlocal effects originating at the wall.
