Rotational behavior of red blood cells in suspension---a mesoscale simulation study

TL;DR

This study uses a mesoscale simulation model based on lattice Boltzmann methods to analyze the collective rotational behavior of red blood cells in suspension, providing insights into their orientation and rotation under flow conditions.

Contribution

It introduces a coarse-grained blood model capable of simulating millions of cells, enabling detailed analysis of cell orientation and rotation in flow, which was previously computationally challenging.

Findings

Quantified cell inclination and nematic order as functions of shear rate and hematocrit.

Recorded distribution of rotation periods, showing a peak near theoretical free cell values.

Demonstrated the model's ability to measure viscosity in flow simulations.

Abstract

The nature of blood as a suspension of red blood cells makes computational hemodynamics a demanding task. Our coarse-grained blood model, which builds on a lattice Boltzmann method for soft particle suspensions, enables the study of the collective behavior of the order of 10^6 cells in suspension. After demonstrating the viscosity measurement in Kolmogorov flow, we focus on the statistical analysis of the cell orientation and rotation in Couette flow. We quantify the average inclination with respect to the flow and the nematic order as a function of shear rate and hematocrit. We further record the distribution of rotation periods around the vorticity direction and find a pronounced peak in the vicinity of the theoretical value for free model cells even though cell-cell interactions manifest themselves in a substantial width of the distribution.