Enhanced axial migration of a deformable capsule in pulsatile channel flows

TL;DR

This study numerically investigates how pulsatile flow enhances the lateral migration speed of deformable capsules in channels, revealing frequency-specific effects relevant to biological flows and cell manipulation techniques.

Contribution

It demonstrates that flow pulsation can accelerate capsule migration at specific frequencies, providing new insights into cell flow mechanics in pulsatile environments.

Findings

Migration speed increases with oscillatory amplitude.

Most effective frequency remains unchanged regardless of amplitude.

Pulsatile flows influence deformable particle dynamics in physiological conditions.

Abstract

We present numerical analysis of the lateral movement of a deformable spherical capsule in a pulsatile channel flow, with a Newtonian fluid in almost inertialess condition and at a small confinement ratio $a_0/R = 0.4$, where $R$ and $a$ are the channel and capsule radius. We find that the speed of the axial migration of the capsule can be accelerated by the flow pulsation at a specific frequency. The migration speed increases with the oscillatory amplitude, while the most effective frequency remains basically unchanged and independent of the amplitude. Our numerical results form a fundamental basis for further studies on cellular flow mechanics, since pulsatile flows are physiologically relevant in human circulation, potentially affecting the dynamics of deformable particles and red blood cells (RBCs), and can also be potentially exploited in cell focusing techniques.