Characterization of chaotic motion in a rotating drum

TL;DR

This study investigates chaotic motion in a rotating drum with spheres, revealing various behaviors including chaotic states, and demonstrates how simple fluid-particle systems can exhibit complex dynamical phenomena.

Contribution

It provides a detailed experimental characterization of chaotic behaviors in a fluid-filled rotating drum with multiple spheres, highlighting new insights into fluid dynamical chaos.

Findings

Identification of multiple dynamic states including chaotic motion.

Chaotic states are highly unpredictable and complex.

The system serves as a simple model for fluid dynamical chaos.

Abstract

Numerous studies have demonstrated the potential for simple fluid plus particle systems to produce complicated dynamical behavior. In this work, we study a horizontal rotating drum filled with pure glycerol and three large, heavy spheres. The rotation of the drum causes the spheres to cascade and tumble and thus interact with each other. We find several different behaviors of the spheres depending on the drum rotation rate. Simpler states include the spheres remaining well separated, or states where two or all three of the spheres come together and cascade together. We also see two more complex states, where two or three of the spheres move chaotically. We characterize these chaotic states and find that in many respects they are quite unpredictable. This experiment serves as a simple model system to demonstrate chaotic behavior in fluid dynamical systems.