Irregular dynamics of cellular blood flow in a model microvessel

Area of Science:

• Fluid dynamics
• Biophysics
• Computational biology

Background:

• Red blood cell (RBC) flow in narrow cylindrical vessels is complex and irregular.
• Understanding RBC kinematics is crucial for developing accurate reduced-order models.

Purpose of the Study:

• To characterize the chaotic kinematics of RBCs in long-time-series simulations.
• To inform the development of reduced-order models for RBC flow.
• To investigate the underlying dynamics of RBC movement in microcirculation.

Main Methods:

• Long-time-series simulations of RBCs flowing through cylindrical vessels (10^5 diameters).
• Full coupling model between elastic RBC membranes and surrounding viscous fluid.
• Phase-space reconstructions to analyze flow dynamics and attractor existence.

Main Results:

• RBC flow exhibits chaotic kinematics, sensitive to initial conditions, consistent with Lagrangian turbulence.
• No classifiable recurrent features or dominant frequencies were observed in the flow.
• Phase-space analysis indicated no low-dimensional attractor, suggesting effectively stochastic long-time dynamics.

Conclusions:

• The long-time dynamics of RBC flow in these conditions are stochastic.
• A simple Markov chain model was developed and validated against simulation statistics.
• This model effectively reproduces the statistical properties of RBC positions, offering a new tool for analysis.