Complex dynamics of knotted filaments in shear flow

TL;DR

This study uses coarse-grained simulations to explore the complex and diverse dynamic behaviors of knotted filaments in shear flow, revealing both rigid rotation and intricate motion modes influenced by filament properties.

Contribution

It introduces a detailed simulation analysis of knotted filament dynamics in shear flow, highlighting the role of a key dimensionless parameter in mode selection.

Findings

Knotted filaments can rotate rigidly or exhibit complex motions.

The dynamics depend on a dimensionless number involving filament length, elasticity, and shear rate.

Multiple regular and chaotic motion modes are identified.

Abstract

Coarse-grained simulations are used to demonstrate that knotted filaments in shear flow at zero Reynolds number exhibit remarkably rich dynamic behaviour. For stiff filaments that are weakly deformed by the shear forces, the knotted filaments rotate like rigid objects in the flow. But away from this regime the interplay between between shear forces and the flexibility of the filament leads to intricate regular and chaotic modes of motion that can be divided into distinct families. The set of accessible mode families depends to first order on a dimensionless number that relates the filament length, the elastic modulus, the friction per unit length and the shear rate.