Vesicles and red blood cells under shear and Poiseuille flow

Thursday, December 10, 2009 - 9:40am - 10:20am
EE/CS 3-180
Chaouqi Misbah (Université de Grenoble I (Joseph Fourier))
Keywords: Blood flow, microcirculation, modeling, rheology

Abstract: Various rich dynamics of vesicles under linear and nonlinear
flows will be discussed. We present analytical and numerical
results on tank-treading motion, tumbling and
vacillating-breathing (aka swinging, trembling). We then
discuss the notion of transverse migration due to a wall and to
a nonlinear flow. We show theoretical and exeprimental results
on the law of transverse migration in a microfluidic device.
Finally, we present very recent results on a longstadning
puzzle of the blood microcirculatory research: why do red blood
cells adopt a non symmetric shape (called slipper) in small
blood vessels?

A key result of our study is that the parachute symmetric
shape is shown to be unstable, while the slipper shape is
stable. That is, small flow disturbances–which are always
present in real blood flows–cause RBCs to assume slipper
shapes. It is further shown that the slipper shape offers a
better transport efficiency to RBCs. In addition the slipper
shape favors hemoglobin mixing in the cell, and thus enhances
oxygen transport efficiency. Blood flow efficiency together
with optimal oxygen supply seem to be determinant for natural
selection of slipper shapes.
MSC Code: