Regensburg 2007 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 24: Poster I

DY 24.60: Poster

Wednesday, March 28, 2007, 16:00–18:00, Poster D

Higher-order study of vesicle dynamics in shear flow — •Gerrit Danker and Chaouqi Misbah — LSP, UJF-Grenoble 1 and CNRS, BP 87, 38402 Saint Martin d’Hères, France

Vesicles, which consist of a closed fluid membrane surrounding a Newtonian liquid, have been studied extensively in recent years. They can, for example, act as simple mechanical models of biological cells in an external flow, giving insights into challenging problems like blood rheology.

Recent experiments [1] and theoretical studies in the small excess area limit [2] demonstrate that vesicles in a shear flow display different dynamical behaviour, depending on the viscosity contrast between inner and outer fluid. For small viscosity contrast one observes a time-independent vesicle shape with fixed orientation in the flow (tank-treading) and for sufficiently large viscosity ratio an unsteady motion (either tumbling or vacillating-breathing). We extend the analytical study in [2] to higher order in the excess area and discuss consequences for vesicle dynamics and applications to rheology of dilute vesicle suspensions [3].

[1] V. Kantsler and V. Steinberg, Phys. Rev. Lett. 96, 036001 (2006).

[2] C. Misbah, Phys. Rev. Lett. 96, 028104 (2006).

[3] G. Danker and C. Misbah, preprint (2006).