Numerical Simulation of Cell Motion in Microchannels

An immersed boundary method combined with an elastic spring model is applied to simulate the red blood cell (RBC) motion and deformation in bounded Poiseuille flows. As a benchmarking test, the dynamical behavior of a RBC in shear flow is presented. The combined effects of the deformability, the degree of confinement, and the shear gradient of the Poiseuille flow make the RBCs migrate toward a certain cross-sectional equilibrium position, which lies at or off the center line. Two motions of oscillation and swing of RBCs are observed in the narrow channel. Parachute shape and bullet-like shape, depending on the initial angle, coexist for the elliptic shape cell with a low fluid velocity in a narrower channel. The details of the equilibrium shape and position versus the Reynolds number are investigated. Interactions of many cells in Poiseuille flows are studied to examine the size of the cell-free layer and Fahraeus-Lindqvist effect.