Spinning and tumbling of micron-sized triangles in a micro-channel shear flow

TL;DR

This study investigates the angular motion of micron-sized triangular particles in micro-channel shear flow, revealing complex doubly-periodic spinning and tumbling behaviors influenced by particle shape and flow conditions.

Contribution

It provides the first detailed measurements of triangular particle dynamics in shear flow, demonstrating their unique doubly-periodic spinning and tumbling patterns.

Findings

Triangular particles spin and tumble similarly to spheroids in shear flow.

Spinning frequency differs from tumbling frequency, showing complex interactions.

Spinning is directly observable due to particle corners.

Abstract

We report on measurements of the angular dynamics of micron-sized equilaterally triangular platelets suspended in a micro-channel shear flow. Our measurements confirm that such particles spin and tumble like a spheroid in a simple shear. Since the triangle has corners we can observe the spinning directly. In general the spinning frequency is different from the tumbling frequency, and the spinning is affected by tumbling. This gives rise to doubly-periodic angular dynamics.