Sediment grain shape effects on industrial and geophysical flows

What is it about?

Granular materials like cereal, pharmaceuticals, sand, and concrete commonly organize such that grains segregate according to size rather than uniformly mixing. For example, in a jar of nuts, the largest ones are commonly found at the top. Here, we use computer simulations to explore how grain shape controls this phenomenon in industrial and natural settings. We find that even small differences in shape can substantially change the amount and style of segregation, with different effects depending on whether the system is wet or dry. This study demonstrates the importance of grain shape in different systems ranging from food and medicine production to geophysical hazards and processes such as landslides, river erosion, and debris flows on Earth and other celestial bodies.

Featured Image

Photo by NEOM on Unsplash

Photo by NEOM on Unsplash

Why is it important?

Granular segregation occurs in a wide variety of settings. It can be a nuisance in industry, for example making it difficult to mix foods, pharmaceuticals and cement. In nature it can change the dynamics of geohazards like landslides, debris flows and river erosion. Despite its ubiquity, granular segregation is challenging to predict. Our work shows that the shape of the grains makes a big difference in how granular materials move and segregate, potentially providing a mechanism to decrease segregation in industrial materials, allowing for a better understanding of natural flows, and paving the way for future work.