Fluid Vesicles with Viscous Membranes in Shear Flow

TL;DR

This paper investigates how membrane viscosity influences vesicle behavior in shear flow, revealing transitions between different motion types and shape transformations through a novel simulation approach.

Contribution

It introduces a new simulation method combining multi-particle collision dynamics with a triangulated membrane model to study viscous membrane effects.

Findings

Vesicles transition from steady tank-treading to tumbling with increased membrane viscosity.

Shear flow induces shape transformations depending on membrane viscosity and reduced volume.

A simplified model explains the observed dynamical behaviors.

Abstract

The effect of membrane viscosity on the dynamics of vesicles in shear flow is studied. We present a new simulation technique, which combines three-dimensional multi-particle collision dynamics for the solvent with a dynamically-triangulated membrane model. Vesicles are found to transit from steady tank-treading to unsteady tumbling motion with increasing membrane viscosity. Depending on the reduced volume and membrane viscosity, shear can induce both discocyte-to-prolate and prolate-to-discocyte transformations. This dynamical behavior can be understood from a simplified model.