Shape dynamics of a red blood cell in Poiseuille flow

TL;DR

This study uses numerical simulations to analyze red blood cell shape dynamics in Poiseuille flow, revealing bistability between slipper and croissant shapes influenced by viscosity contrast and confinement.

Contribution

It provides detailed phase diagrams of RBC dynamics in confined flow, highlighting the role of viscosity contrast in shape bistability, extending previous vesicle studies.

Findings

Bistability between slipper and croissant shapes observed.

Viscosity contrast influences RBC shape dynamics.

Phase diagrams map RBC behaviors under various conditions.

Abstract

We use numerical simulations to study the dynamics of red blood cells (RBCs) in unconfined and confined Poiseuille flow. Previous numerical studies with 3D vesicles have indicated that the slipper shape observed in experiments at high capillary number can be attributed to the bistability due to the interplay of wall push and outward migration tendency at higher viscosity contrasts. In this paper, we study this outward migration and bistability using numerical simulations for 3D capsules and provide phase diagrams of RBC dynamics with and without viscosity contrast. We observe a bistability of slipper and croissants in confined Poiseuille flow with viscosity contrast as observed in experiments.