# Modified Archimedes' principle predicts rising and sinking of intruders in sheared granular flows

## TL;DR

This study computationally investigates the forces on intruder particles in sheared granular flows, revealing deviations from classical buoyancy and proposing a modified Archimedes' principle that predicts particle rising or sinking.

## Contribution

It introduces a simple force model that accurately predicts intruder behavior based solely on size and density ratios in various flow conditions.

## Key findings

- Force on intruders scales with but deviates from classical buoyancy.
- Deviation depends only on size ratio, not density or flow conditions.
- Proposed model predicts rising or sinking behavior successfully.

## Abstract

We computationally determine the force on single spherical intruder particles in sheared granular flows as a function of particle size, particle density, shear rate, overburden pressure, and gravitational acceleration. The force scales similarly to, but deviates from, the buoyancy force predicted by Archimedes' principle. The deviation depends only on the intruder to bed particle size ratio, but not the density ratio or flow conditions. We propose a simple force model that successfully predicts whether intruders rise or sink, knowing only the size and density ratios, for a variety of flow configurations in physical experiments.