Dynamics of multicomponent vesicles in a viscous fluid

JOURNAL OF COMPUTATIONAL PHYSICS

卷:229

Article

Sohn, Jin Sun¹  Tseng, Yu-Hau^1,2  Li, Shuwang³  Voigt, Axel⁴  Lowengrub, John S.¹ 

[1] Univ Calif Irvine, Dept Math, Irvine, CA 92717 USA

[2] Natl Chiao Tung Univ, Dept Appl Math, Hsinchu 300, Taiwan

[3] IIT, Dept Appl Math, Chicago, IL 60616 USA

[4] Tech Univ Dresden, Dresden, Germany

关键词: Multicomponent vesicle;    Ordered and disordered lipid phases;    Rafts;    Line tension;    Bending stiffness;    Inextensibility;    Boundary integral method;    Small scale decomposition;    Stokes flow;   

DOI  :  10.1016/j.jcp.2009.09.017

来源: Elsevier

【 摘 要 】

We develop and investigate numerically a thermodynamically consistent model of two-dimensional multicomponent vesicles in an incompressible viscous fluid. The model is derived using an energy variation approach that accounts for different lipid surface phases, the excess energy (line energy) associated with surface phase domain boundaries, bending energy, spontaneous curvature, local inextensibility and fluid flow via the Stokes equations. The equations are high-order (fourth order) nonlinear and nonlocal due to incompressibility of the fluid and the local inextensibility of the vesicle membrane. To solve the equations numerically, we develop a nonstiff, pseudo-spectral boundary integral method that relies on an analysis of the equations at small scales. The algorithm is closely related to that developed very recently by Veerapaneni et al. [81] for homogeneous vesicles although we use a different and more efficient time stepping algorithm and a reformulation of the inextensibility equation. We present simulations of multicomponent vesicles in an initially quiescent fluid and investigate the effect of varying the average surface concentration of an initially unstable mixture of lipid phases. The phases then redistribute and alter the morphology of the vesicle and its dynamics. When an applied shear is introduced, an initially elliptical vesicle tank-treads and attains a steady shape and surface phase distribution. A sufficiently elongated vesicle tumbles and the presence of different surface phases with different bending stiffnesses and spontaneous curvatures yields a complex evolution of the vesicle morphology as the vesicle bends in regions where the bending stiffness and spontaneous curvature are small. (C) 2009 Elsevier Inc. All rights reserved.

【 授权许可】

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