Dynamics of a non-spherical microcapsule with incompressible interface in shear flow

Document Type

Article

Publication Date

7-10-2011

Abstract

We study the motion and deformation of a liquid capsule enclosed by a surface-incompressible membrane as a model of red blood cell dynamics in shear flow. Considering a slightly ellipsoidal initial shape, an analytical solution to the creeping-flow equations is obtained as a regular perturbation expansion in the excess area. The analysis takes into account the membrane fluidity, area-incompressibility and resistance to bending. The theory captures the observed transition from tumbling to swinging as the shear rate increases and clarifies the effect of capsule deformability. Near the transition, intermittent behaviour (swinging periodically interrupted by a tumble) is found only if the capsule deforms in the shear plane and does not undergo stretching or compression along the vorticity direction; the intermittency disappears if deformation along the vorticity direction occurs, i.e. if the capsule 'breathes'. We report the phase diagram of capsule motions as a function of viscosity ratio, non-sphericity and dimensionless shear rate. © 2011 Cambridge University Press.

Identifier

79960144154 (Scopus)

Publication Title

Journal of Fluid Mechanics

External Full Text Location

https://doi.org/10.1017/jfm.2011.108

e-ISSN

14697645

ISSN

00221120

First Page

221

Last Page

247

Volume

678

Grant

CBET-0846247

Fund Ref

National Science Foundation

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