Effect of tube diameter and capillary number on platelet margination and near-wall dynamics

Abstract

The effect of tube diameter $D$ and capillary number $Ca$ on platelet margination in blood flow at $\approx 37\%$ tube haematocrit is investigated. The system is modelled as three-dimensional suspension of deformable red blood cells and nearly rigid platelets using a combination of the lattice-Boltzmann, immersed boundary and finite element methods. Results show that margination is facilitated by a non-diffusive radial platelet transport. This effect is important near the edge of the cell-free layer, but it is only observed for $Ca>0.2$, when red blood cells are tank-treading rather than tumbling. It is also shown that platelet trapping in the cell-free layer is reversible for $Ca\le 0.2$. Only for the smallest investigated tube ($D=10\mu \text{m}$) margination is essentially independent of $Ca$. Once platelets have reached the cell-free layer, they tend to slide rather than tumble. The tumbling rate is essentially independent of $Ca$ but increases with $D$. Tumbling is suppressed by the strong confinement due to the relatively small cell-free layer thickness at $\approx 37\%$ tube haematocrit.

16 pages, 10 figures

References in corpus (3)

• Efficient and accurate simulations of deformable particles immersed in a fluid using a combined immersed boundary lattice Boltzmann finite element method
• Mechanism of margination in confined flows of blood and other multicomponent suspensions
• Parallelised Hoshen-Kopelman algorithm for lattice-Boltzmann simulations

Cited by in corpus (6)

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• Clustering of microscopic particles in constricted blood flow
• Lift at low Reynolds number
• Anti-margination of microparticles and platelets in the vicinity of branching vessels
• A unified analysis of nano-to-microscale particle dispersion in tubular blood flow
• Mesoscale simulation of soft particles with tunable contact angle in multi-component fluids