Physical Review Letters
Blood microcirculation critically depends on the migration of red cells towards the flow centerline. We identify theoretically the ratio of the inner over the outer fluid viscosities λ as a key parameter. At low λ, the vesicle deforms into a tank-treading ellipsoid shape far away from the flow centerline. The migration is always towards the flow centerline, unlike drops. Above a critical λ, the vesicle tumbles or breaths and migration is suppressed. A surprising coexistence of two types of shapes at the centerline, a bulletlike and a parachutelike shape, is predicted.
Danker, Gerrit; Vlahovska, Petia M.; and Misbah, Chaouqi, "Vesicles in Poiseuille Flow" (2009). Open Dartmouth: Faculty Open Access Articles. 3536.