Relaxation-type nonlocal inertial-number rheology for dry granular flows.
Relaxation-type nonlocal inertial-number rheology for dry granular flows.
复制标题
DOI：
10.1103/physreve.96.062909
复制
发表时间：
2017-12
期刊：
影响因子：
--
通讯作者：
Keng-Lin Lee;Fu-Ling Yang
中科院分区：
文献类型：
--
作者：
Keng-Lin Lee;Fu-Ling Yang
我们提出了一种本构模型来描述干燥颗粒材料的非局域性、滞后性和几种流动特征。采用众所周知的惯性数 I 作为剪切引起的局部流化的量度，我们根据雪崩和耗散过程中微观结构的演变推导出 I 的松弛模型。该模型产生均匀流动的非单调流动定律，解释了准静态流动中的滞后固-液转变和间歇性。对于非均匀流动，该模型预测广义巴尼尔德剪切应力，揭示两种微观非局部机制的相互作用：相关结构之间的碰撞和结构内流化的扩散。在描述沿斜坡向下的均匀流动时，该模型再现了滞后起始和停止高度以及平均速度的普利肯流动规则。此外，还发现了反映流动非局部效应的无量纲参数，该参数控制巴尼尔德流动动力学和蠕动流动动力学之间的过渡。
We propose a constitutive model to describe the nonlocality, hysteresis, and several flow features of dry granular materials. Taking the well-known inertial number I as a measure of sheared-induced local fluidization, we derive a relaxation model for I according to the evolution of microstructure during avalanche and dissipation processes. The model yields a nonmonotonic flow law for a homogeneous flow, accounting for hysteretic solid-fluid transition and intermittency in quasistatic flows. For an inhomogeneous flow, the model predicts a generalized Bagnold shear stress revealing the interplay of two microscopic nonlocal mechanisms: collisions among correlated structures and the diffusion of fluidization within the structures. In describing a uniform flow down an incline, the model reproduces the hysteretic starting and stopping heights and the Pouliquen flow rule for mean velocity. Moreover, a dimensionless parameter reflecting the nonlocal effect on the flow is discovered, which controls the transition between Bagnold and creeping flow dynamics.