The discharge of elongated particles from a silo with rotating bottom is investigated numerically. The introduction of a slight transverse shear reduces the flow rate $Q$ by up to 70% compared with stationary bottom, but the flow rate shows a modest increase by further increasing the external shear. Focusing on the dependency of flow rate $Q$ on orifice diameter $D$, the spheres and rods show two distinct trends. For rods, in the small-aperture limit $Q$ seems to follow an exponential trend, deviating from the classical power-law dependence. These macroscopic observations are in good agreement with our earlier experimental findings [Phys. Rev. E 103, 062905 (2021)]. With the help of the coarse-graining methodology we obtain the spatial distribution of the macroscopic density, velocity, kinetic pressure, and orientation fields. This allows us detecting a transition from funnel to mass flow pattern caused by the external shear. Additionally, averaging these fields in the region of the orifice reveals that the strong initial decrease in $Q$ is mostly attributed to changes in the flow velocity, while the weakly increasing trend at higher rotation rates is related to increasing packing fraction. Similar analysis of the grain orientation at the orifice suggests a correlation of the flow rate magnitude with the vertical orientation and the packing fraction at the orifice with the order of the grains. Lastly, the vertical profile of mean acceleration at the center of the silo denotes that the region where the acceleration is not negligible shrinks significantly due to the strong perturbation induced by the moving wall.

中文翻译：

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在旋转剪切下排出筒仓中的细长颗粒

数值研究了旋转底部筒仓中细长颗粒的排放。引入轻微的横向剪切会降低流速$问$与静止底部相比最多增加 70%，但通过进一步增加外部剪切，流速显示出适度的增加。关注流量的依赖性$问$在孔口直径上$D$，球体和棒显示出两种不同的趋势。对于棒，在小孔径极限$问$似乎遵循指数趋势，偏离经典的幂律依赖。这些宏观观察结果与我们早期的实验结果非常一致 [ Phys. 修订版 E 103，062905 (2021)]。在粗粒度方法的帮助下，我们获得了宏观密度、速度、动压和方向场的空间分布。这使我们能够检测到由外部剪切引起的从漏斗到质量流模式的转变。此外，对孔口区域的这些场进行平均表明，$问$主要归因于流速的变化，而在较高转速下的微弱增加趋势与增加填充率有关。对孔口处晶粒取向的类似分析表明，流速大小与垂直取向以及孔口处的填充率与晶粒顺序之间存在相关性。最后，筒仓中心的平均加速度垂直剖面表明，由于移动壁引起的强烈扰动，加速度不可忽略的区域显着收缩。