Jet-induced jammed states of granular jet impacts
Jet-induced jammed states of granular jet impacts
复制标题
DOI：
10.1093/ptep/ptt078
复制
发表时间：
2013-02
影响因子：
3.5
通讯作者：
T. Sano;H. Hayakawa
中科院分区：
文献类型：
--
作者：
T. Sano;H. Hayakawa
数值研究了颗粒射流对二维有摩擦颗粒和无摩擦颗粒的冲击。在冲击过程中出现了一个带有死区的稠密流。从我们的二维模拟，我们评估的状态方程和本构方程的流动。在无摩擦情况下，压力和切应力的渐近发散与堵塞转变附近的情况相似，但其指数小于剪切颗粒系统的指数，且接近于动力学理论的外推结果.与摩擦颗粒堵塞相似，临界密度随颗粒摩擦常数的增大而减小。对于双分散体系，定义为剪切应力与法向应力之比的有效摩擦常数随着应变率的增加从接近零开始单调增加。另一方面，对于单分散体系，由于结晶态和液态的共存，有效摩擦常数具有两个亚稳分支。
The impacts of granular jets for both frictional and frictionless grains in two dimensions are numerically investigated. A dense flow with a dead zone emerges during the impact. From our two-dimensional simulation, we evaluate the equations of state and the con- stitutive equations of the flow. The asymptotic divergences of pressure and shear stress similar to the situation near the jamming transition appear for the frictionless case, while their exponents are smaller than those of the sheared granular systems, and are close to the extrapolation from the kinetic theoretical regime. In a similar manner to the jam- ming for frictional grains, the critical density decreases as the friction constant of grains increases. For bi-disperse systems, the effective friction constant defined as the ratio of shear stress to normal stress, monotonically increases from near zero, as the strain rate increases. On the other hand, the effective friction constant has two metastable branches for mono-disperse systems because of the coexistence of a crystallized state and a liquid state.