Swinging and tumbling of multicomponent vesicles in flow
Swinging and tumbling of multicomponent vesicles in flow
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DOI：
10.1017/jfm.2022.40
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发表时间：
2022-02-03
影响因子：
3.7
通讯作者：
Spagnolie, Saverio E.
中科院分区：
文献类型：
--
作者：
Gera, Prerna;Salac, David;Spagnolie, Saverio E.
生物膜是蛋白质和分子的宿主，这些蛋白质和分子可以形成结构域样结构，从而导致空间变化的材料特性。具有这种异质膜的囊泡可以在平衡时表现出复杂的形状，并且当被置于流动中时表现出丰富的动力学。在小变形和二维系统的假设下，我们建立了一个降阶模型来描述粘性背景剪切流和具有空间变化的弯曲刚度和自发曲率的不可伸展膜之间的流体-结构相互作用。相对于流速和内部/外部粘度对比，临界量级的材料性质变化可以引发囊泡动力学的质的变化。几乎恒定的弯曲刚度或自发曲率的膜经历小幅度的摆动运动（其包括切向坦克踩踏），而对于足够大的材料变化，动力学通过以膜材料的翻滚和周期性相位滞后为特征的制度，并且最终对于非常大的材料变化为刚体翻滚行为。域分布的偶数和奇数的空间模式被发现有明显的差异。充分的数值模拟被用来探测的理论预测，这似乎是有效的，即使在研究大幅变形膜。
Biological membranes are host to proteins and molecules which may form domain-like structures resulting in spatially varying material properties. Vesicles with such heterogeneous membranes can exhibit intricate shapes at equilibrium and rich dynamics when placed into a flow. Under the assumption of small deformations and a two-dimensional system, we develop a reduced-order model to describe the fluid-structure interaction between a viscous background shear flow and an inextensible membrane with spatially varying bending stiffness and spontaneous curvature. Material property variations of a critical magnitude, relative to the flow rate and internal/external viscosity contrast, can set off a qualitative change in the vesicle dynamics. A membrane of nearly constant bending stiffness or spontaneous curvature undergoes a small amplitude swinging motion (which includes tangential tank-treading), while for large enough material variations the dynamics pass through a regime featuring tumbling and periodic phase-lagging of the membrane material, and ultimately for very large material variation to a rigid-body tumbling behaviour. Distinct differences are found for even and odd spatial modes of domain distribution. Full numerical simulations are used to probe the theoretical predictions, which appear valid even when studying substantially deformed membranes.