FIG. 3.

Sequences of the deformation of two healthy RBCs under flow (a) at high and (b) at low speed and viscosity of the external medium. Along the geometry, both cells get compressed and elongated perpendicular to the flow direction when entering each narrowing and widening, respectively. (a) At high hydrodynamic stress, as the cell exits, it is stretched by the extensional flow before returning to the parachute-like shape, unlike at lower stress (b), where the cell recovers directly from the compression without being stretched. The external viscosity and the cell speed at the exit are, respectively, (a) ${\eta }_{out}=31.5$ mPa s and $V_{cell}=533$ $\mu$m s${}^{-1}$ and (b) ${\eta }_{out}=1.3$ mPa s and $V_{cell}=483$ $\mu$m s${}^{-1}$. The schematics show a representation of the typical deformation in the two behaviors at two different times $t_1$ and $t_2$.