Oblate to prolate transition of a vesicle under flow

Transition de forme Oblate / Prolate d'une vésicule dans un cisaillement simple

Maximilien Degonville (1) , Gwenn Boedec (1) , Marc Leonetti (2)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre
2 LRP - Laboratoire Rhéologie et Procédés

Vesicles are micrometric soft particles whose the membrane is a two-dimensional incompressible fluid governed by bending resistance leading to a zoology of shapes. The dynamics of deflated vesicles in shear flow with a bottom wall, a first minimal configuration to consider confined vesicles is investigated using numerical simulations. Coexistence under flow of oblate (metastable) and prolate (stable) shapes is studied in details. In particular, we discuss the boundaries of the region of coexistence in the (v, Ca) plane where v is the reduced volume of the vesicle and Ca the Capillary number. We characterize the transition from oblate to prolate and analyse the divergence of the transition time near the critical capillary number. We then analyse lift dynamics of oblate vesicle in the weak flow regime.

Domaines: Matière Molle [cond-mat.soft]; Biomécanique [physics.med-ph]; Mécanique des fluides [physics.class-ph]

Maximilien Degonville, Gwenn Boedec, Marc Leonetti. Oblate to prolate transition of a vesicle under flow. European Physical Journal E: Soft matter and biological physics, 2019, ⟨10.1140/epje/i2019-11881-0⟩. ⟨hal-02281221⟩