A continuum mechanics model for the Fåhræus-Lindqvist effect

Area of Science:

• Physiology and Biophysics
• Fluid Dynamics and Rheology

Background:

• The Fåhræus-Lindqvist effect describes the decrease in blood viscosity in tubes smaller than 0.3 mm.
• The underlying physical mechanism of this phenomenon remains incompletely understood.
• Previous explanations, like Haynes' core-annulus model, lack rigorous deduction from continuum dynamics principles.

Purpose of the Study:

• To provide a rigorous, continuum mechanics-based explanation for the Fåhræus-Lindqvist effect.
• To develop a theoretical model for blood apparent relative viscosity.
• To validate the model against experimental data from multiple studies.

Main Methods:

• Application of recent theoretical results from Guadagni and Farina (2020).
• Development of a corrected core-annulus structure model for blood flow.
• Mathematical derivation based on continuum dynamics principles.

Main Results:

• The proposed theoretical model successfully explains the Fåhræus-Lindqvist effect.
• The model's predictions align with the original experimental data of Fåhræus and Lindqvist (1931).
• The model also validates against viscosity data from subsequent researchers.

Conclusions:

• A sound theoretical explanation for the Fåhræus-Lindqvist effect is established using continuum mechanics.
• The developed model provides a robust framework for understanding blood apparent relative viscosity in microcirculation.
• This work bridges the gap between qualitative hypotheses and rigorous fluid dynamics principles.