On POD-based modal analysis in simulations of granular flows
On POD-based modal analysis in simulations of granular flows
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DOI：
10.1016/j.powtec.2022.118058
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发表时间：
2022-11
影响因子：
5.2
通讯作者：
S. Li;Guangtao Duan;M. Sakai
中科院分区：
文献类型：
--
作者：
S. Li;Guangtao Duan;M. Sakai
了解颗粒流的动力学在各种工程领域都具有重要意义，但由于流动的复杂性而具有挑战性。离散单元法(DEM)常用于各种颗粒系统的数值模拟。最近，模态分析被证明显著加深了对这些系统的理解。模态分析的原理是从实验或数值数据集中提取一组主要结构。在本研究中，一种先进的模式分析技术，即基于Lanczos的本征正交分解(LPOD)被引入到粒子系统的数值模拟中。介绍了两种类型的应用。首先，采用基于LPOD技术的模态分析方法对滚筒内的颗粒混合进行了评价。结果表明，粒子运动的POD模分布可以揭示出主要的机制，如对流/扩散。其次，采用基于LPOD技术的模式分析方法，验证了喷动床中粗粒DEM的充分性。结果表明，在原始粒子和粗粒粒子系统中观察到了相似的POD模式和相关的能谱。因此，POD分析不仅可以用来识别主要的混合机制，而且POD结果也被证明是验证粗粒DEM的新的有效参数。
Understanding the dynamics of granular flows is of great significance in various engineering fields but challenging because of flow complexity. The discrete element method (DEM) is often employed in simulations of various granular systems. Recently, modal analysis has been shown to remarkably deepen the understanding of these systems. The principle of the modal analysis is to extract a set of dominant structures from experimental or numerical datasets. In this study, an advanced modal analysis technique, i.e., the Lanczos-based proper orthogonal decomposition (LPOD), is incorporated into numerical simulations of a particle system. Two types of applications are presented. First, the modal analysis based on the LPOD technique is adopted to evaluate particle mixing in a rolling drum. It is demonstrated that the POD-mode distributions of particle movements can reveal dominant mechanisms, such as convection/diffusion. Second, the LPOD technique based modal analysis is employed to validate the adequacy of a coarse-grained DEM in a spouted bed. The results show that similar patterns of POD modes and related energy spectra are observed in the original particle and the coarse-grained particle systems. Consequently, not only can POD analysis be used to identify main mixing mechanisms, but also POD results are shown to be new effective parameters in the validation of the coarse-grained DEM.