Numerical investigation on red blood cell flow based on unstructured grid.

Area of Science:

• * Biophysics and Computational Biology
• * Fluid Dynamics
• * Hematology

Background:

• * Simulating blood cell flow in intricate vasculature is challenging.
• * Red blood cell (RBC) behavior significantly impacts blood rheology.
• * Understanding RBC dynamics is crucial for diagnosing and treating blood disorders.

Purpose of the Study:

• * To establish a validated mechanical model for RBCs in complex blood vessels.
• * To investigate RBC morphology and blood viscosity in microcirculation.
• * To explore the influence of malaria on RBC deformability and blood viscosity.

Main Methods:

• * Developed an RBC mechanical model using an unstructured grid.
• * Employed Skalak's strain-energy function and hinge springs for membrane mechanics.
• * Utilized the immersed boundary method for fluid-structure interaction.
• * Validated the model against experimental RBC stretching data.

Main Results:

• * The model accurately predicted RBC stretching behavior.
• * Observed RBCs adopting a parachute shape in narrow vessels.
• * Identified buckling instability in RBCs under specific flow conditions.
• * Demonstrated the reverse Fahraeus-Lindqvist effect at ~10 μm vessel diameter.
• * Found a linear relationship between blood apparent viscosity and hematocrit.
• * Confirmed decreased RBC deformability and increased viscosity due to malaria infection.

Conclusions:

• * The developed model provides a reliable tool for studying RBC flow in complex geometries.
• * RBC morphology and flow dynamics are significantly altered in microcirculation.
• * Malaria infection adversely affects RBC mechanics and blood rheology.