Eur. Phys. J. E (2019) 42: 116
https://doi.org/10.1140/epje/i2019-11881-0

Regular Article

Oblate to prolate transition of a vesicle in shear flow

¹ Aix Marseille Univ, CNRS, Centrale Marseille, IRPHE UMR 7342, 13384, Marseille, France
² Univ. Grenoble Alpes, CNRS, Grenoble INP, LRP, Grenoble, France

^* e-mail: gwenn.boedec@univ-amu.fr
^** e-mail: marc.leonetti@univ-grenoble-alpes.fr

Received: 17 May 2019
Accepted: 2 August 2019
Published online: 5 September 2019

Abstract

Vesicles are micrometric soft particles whose 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 the lift dynamics of an oblate vesicle in the weak flow regime.