Movement of a spherical cell in capillaries using a boundary element method

Area of Science:

• Fluid dynamics
• Biophysics
• Computational mechanics

Background:

• Particle behavior in confined geometries is crucial for understanding microfluidic systems and biological transport.
• Previous methods faced limitations in accurately modeling particle dynamics near capillary walls.

Purpose of the Study:

• To investigate the translation and rotation of spherical particles within capillaries using an advanced numerical method.
• To overcome limitations of prior studies, particularly for eccentrically positioned particles and small clearances.

Main Methods:

• Utilized the boundary element method (BEM) for simulating fluid-particle interactions in a Newtonian viscous fluid within a cylindrical capillary.
• Calculated particle velocity and rotation from equilibrium equations under gravity-driven flow and pressure gradients.

Main Results:

• BEM results show excellent agreement (<1% difference) with Bohlin's analytical solution for co-centric spheres.
• BEM offers improved estimations of sphere velocity and rotation compared to boundary singularity methods (BSM), especially for small particle-wall gaps.
• The study successfully modeled particle movement under pressure gradients, relevant to blood cell dynamics.

Conclusions:

• The boundary element method (BEM) is a powerful tool for accurately simulating spherical particle dynamics in capillaries.
• BEM enhances the understanding of particle behavior in confined spaces, with implications for microfluidics and cell transport.
• This approach enables detailed investigation of cell movement in close proximity to capillary walls.