A terminal-velocity model for super-ellipsoidal particles

The prediction of the terminal velocity of non-spherical particles, such as sediments and microplastics, is essential for understanding their transport processes in rivers or marine environments. However, most of the existing models have been proposed based on specific particle materials, and there is a lack of system-atic research on the effects of different shape factors on terminal velocity. In this study, super-ellipsoidal particles were selected as test particles for settling experiments, and a particle-velocity tracking code was developed to measure their terminal velocities during falling through glycerin-water mixtures. A terminal-velocity model for super-ellipsoidal particles was proposed based on the measured data. Owing to the new model, multivalued predictions of the terminal velocity based on a single shape factor, such as sphericity and Corey shape factor, were disclosed, and the prediction errors were evaluated. The results of this study can provide a basis for establishing a general terminal-velocity model that considers the influence of particle shape.(c) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

The prediction of terminal velocity for non-spherical particles is crucial for understanding their transport processes. However, existing models lack systematic research on the effects of different shape factors on terminal velocity. This study used super-ellipsoidal particles as test particles and proposed a terminal-velocity model based on measured data. The study revealed multivalued predictions and evaluated the prediction errors based on a single shape factor. The results provide a basis for establishing a general terminal-velocity model that considers the influence of particle shape.