Mixing can vary based on the scale at which the system is observed, and a mixing index that can capture the features at different length scales is desirable. In this article, we analyze the scale dependence of the mixing indices developed for Eulerian multiphase models. Relevant length scales are distinguished by filtering solid fraction fields. The scale-dependence study is first done on manufactured fields of solid fraction to assess the performance of the mixing indices. The study is extended to a two-dimensional CFD simulation of the segregation of a bidisperse gas–solid mixture. The local mixing index performs well in capturing the spatial variation of mixing at different scales. The scale dependence of two global mixing indices is considered in the study, where the state of mixing is defined based on statistical measures. We demonstrate that the choice of measures influences the sensitivity of mixing indices to mixing at different scales.

中文翻译：

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欧拉多相模型混合指数的尺度依赖性研究


混合可以根据观察系统的尺度而变化，并且可以捕获不同长度尺度的特征的混合指数是可取的。在本文中，我们分析了为欧拉多相模型开发的混合指数的尺度依赖性。通过过滤固体分数字段来区分相关的长度尺度。首先在固体部分的制造领域进行尺度依赖性研究，以评估混合指数的性能。该研究扩展到双分散气固混合物分离的二维 CFD 模拟。局部混合指数在捕捉不同尺度下混合的空间变化方面表现良好。研究中考虑了两个全局混合指数的尺度依赖性，其中混合状态是基于统计测量来定义的。我们证明，措施的选择会影响混合指数对不同尺度混合的敏感性。