Behavior of active filaments near solid-boundary under linear shear flow

Area of Science:

• Physics
• Soft Matter Physics
• Fluid Dynamics

Background:

• Understanding the behavior of active matter, such as self-propelled filaments, is crucial in various scientific fields.
• Confined geometries and external flows significantly influence the dynamics of these active systems.

Purpose of the Study:

• To investigate the steady-state behavior of self-propelled filaments under Couette flow between planar walls.
• To analyze the impact of hydrodynamics, propulsive force, and shear flow on filament distribution and orientation.

Main Methods:

• Mesoscale simulation approach to model the hydrodynamics of a dilute suspension of self-propelled filaments.
• Detailed analysis of positional and angular probability distributions.

Main Results:

• Filaments show adsorption near walls, diminishing with increasing shear flow (Weissenberg number).
• Excess filament density decreases with Weissenberg number (Wi-β, β ≈ 0.8).
• Orientation near walls is influenced by propulsive force (Pe-1/3) and shear, leading to upstream/downstream swimming and population splitting.

Conclusions:

• The study reveals complex behaviors of active filaments in shear flow, including surface adsorption and orientation changes.
• A transition from unimodal to bimodal population distribution is observed, dependent on the interplay between propulsive force and shear flow.