Wrinkling instability of vesicles in steady linear flow

TL;DR

This study investigates the wrinkling instability of vesicles under high strain rates in steady linear flow, combining experiments, simulations, and a Langevin model to understand thermal fluctuation effects.

Contribution

It provides new experimental and numerical insights into vesicle wrinkling in steady flow and highlights the role of thermal fluctuations through a coupled Langevin model.

Findings

Wrinkling occurs at high strain rates in steady linear flow.

Thermal fluctuations are crucial for the instability.

The model reproduces experimental observations well.

Abstract

We present experimental observations and numerical simulations of a wrinkling instability that occurs at sufficiently high strain rates in the trembling regime of vesicle dynamics in steady linear flow. Spectral and statistical analysis of the data shows similarities and differences with the wrinkling instability observed earlier for vesicles in transient elongation flow. The critical relevance of thermal fluctuations for this phenomenon is revealed by a simple model using coupled Langevin equations that reproduces the experimental observations quite well.