Abstract

We apply proper orthogonal decomposition (POD) technique to analyze granular rheology in a laboratory-scale pulsed-fluidized bed. POD allows us to describe the inherent dynamics and energy budget in the dominant spatio-temporal modes in addition to identifying spatial coherence. This enables us to elucidate non-linear interactions between the different mechanisms which has been a shortcoming of conventional statistics-based approaches. The bubbling pattern is a result of interplay between the harmonic and sub-harmonic components. The mesoscopic flow features which contribute to the pattern are dependent on the modal energy budget which change with the pulsing frequency. It is also observed that the granular dynamics can be sufficiently reconstructed by the leading POD modes despite the presence of bubbles which represent kinematic shocks contributing to higher-order modes. In short, we highlight the utility of POD while analyzing fluidized granular flows, and pave the way for future analyses.

Graphic abstract

中文翻译：

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使用适当的正交分解来阐明颗粒流中的特征

摘要

我们应用适当的正交分解（POD）技术来分析实验室规模的脉冲流化床中的颗粒流变学。POD允许我们除了识别空间连贯性外，还可以描述主要时空模式下的内在动力学和能量收支。这使我们能够阐明不同机制之间的非线性相互作用，这是传统的基于统计的方法的缺点。起泡模式是谐波分量和次谐波分量之间相互作用的结果。促成模式的介观流动特征取决于随脉冲频率变化的模态能量预算。还观察到，尽管存在代表运动冲击的气泡，但通过领先的POD模式可以充分地重构颗粒动力学，而运动气泡对高次模式做出了贡献。简而言之，我们着重介绍了POD在分析流化颗粒流时的效用，并为将来的分析铺平了道路。

图形摘要