Tumbling of lipid vesicles, enclosing a viscous fluid, under a shear flow
Tumbling of lipid vesicles, enclosing a viscous fluid, under a shear flow
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脂质囊泡在剪切流下翻滚，包裹着粘性液体
DOI：
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发表时间：
2005
影响因子：
0.5
通讯作者：
Thomas Podgorski
中科院分区：
文献类型：
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作者：
V. Vitkova;M. Mader;T. Biben;Thomas Podgorski
我们对瘪泡的翻滚运动进行了实验研究，当被囊泡膜包围的流体的粘度η in充分高于外部水溶液的粘度η ut时。使具有在0.74至0.96范围内的减小的体积（囊泡体积与具有相同表面积的球体的体积之间的比率）的囊泡经受简单剪切流，并且表征囊泡翻滚运动的各种粘度对比（r = η in/η out，范围为9.6至28.3）。实验揭示了一个强大的效果囊泡变形性（高灵活性的脂质膜）的翻滚运动在流体动力学领域：囊泡形状显着改变在旋转过程中，影响旋转速度和角度之间的关系。对于变形较小的囊泡（较高的减少体积或较低的毛细管数），实验运动是在较好的协议与简单的分析模型固定形状的椭圆形囊泡。我们比较实验测量与数值计算结果，通过边界积分方法获得。
We performed an experimental study of the tumbling motion of deflated lipid vesicles, when the viscosity, η i n , of the fluid, enclosed by the vesicle membrane, is sufficiently higher than that, η o u t , of the outer aqueous solution. Vesicles with reduced volumes (the ratio between the vesicle volume and the volume of a sphere, having the same surface area) in the range 0.74 to 0.96 were subjected to a simple shear flow, and the vesicle tumbling motion was characterized for various viscosity contrasts (r = η i n /η o u t ranging from 9.6 to 28.3). Experiments reveal a strong effect of vesicle deformability (high flexibility of the lipid membrane) on the tumbling motion in a hydrodynamic field: the vesicle shape significantly changes during the rotation, influencing the relationship between rotation speed and angle. For less deformable vesicles (higher reduced volume or lower capillary number), the experimental motion is in good agreement with simpler analytical models for fixed shape ellipsoidal vesicles. We compare the experimental measurements with numerical results, obtained by a boundary integral method.