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arXiv · 2208.00245

Modeling Stratified Segregation in Periodically Driven Granular Heap Flow

Hongyi Xiao·Zhekai Deng·Julio M. Ottino·Paul B. Umbanhowar·Richard M. Lueptow
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Abstract

We present a continuum approach to model segregation of size-bidisperse granular materials in unsteady bounded heap flow as a prototype for modeling segregation in other time varying flows. In experiments, a periodically modulated feed rate produces stratified segregation like that which occurs due to intermittent avalanching, except with greater layer-uniformity and higher average feed rates. Using an advection-diffusion-segregation equation and characterizing transient changes in deposition and erosion after a feed rate change, we model stratification for varying feed rates and periods. Feed rate modulation in heap flows can create well-segregated layers, which effectively mix the deposited material normal to the free surface at lengths greater than the combined layer-thickness. This mitigates the strong streamwise segregation that would otherwise occur at larger particle-size ratios and equivalent steady feed rates and can significantly reduce concentration variation during hopper discharge. Coupling segregation, deposition and erosion is challenging but has many potential applications.

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Hongyi Xiao, Zhekai Deng, Julio M. Ottino, Paul B. Umbanhowar, Richard M. Lueptow. 2022-07-30. Modeling Stratified Segregation in Periodically Driven Granular Heap Flow. https://arxiv.org/abs/2208.00245

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