Geometric visualization of self-propulsion in a complex medium

TL;DR

This paper combines geometric mechanics, experiments, and simulations to analyze and visualize how a simple swimmer moves in granular media, comparing it to swimming in viscous fluids.

Contribution

It introduces a geometric framework for understanding self-propulsion in granular media, validated through experiments and simulations, and compares it to fluid swimming.

Findings

Effective movement patterns are predicted and verified experimentally.

The geometric approach enables visualization and comparison of locomotion in different media.

The study provides insights into the mechanics of swimming in granular media.

Abstract

Combining geometric mechanics theory, laboratory robotic experiment and numerical simulation, we study the locomotion in granular media (GM) of the simplest non-inertial swimmer, the Purcell three-link swimmer. Using granular resistive force laws as inputs, the theory relates translation and rotation of the body to shape changes (movements of the links). This allows analysis, visualization, and prediction of effective movements that are verified by experiment. The geometric approach also facilitates comparison between swimming in GM and in viscous fluids.