Influence of internal viscosity on the large deformation and buckling of a spherical capsule in a simple shear flow
Influence of internal viscosity on the large deformation and buckling of a spherical capsule in a simple shear flow
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DOI：
10.1017/s0022112011000280
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发表时间：
2011-04-01
影响因子：
3.7
通讯作者：
Barthes-Biesel, D.
中科院分区：
文献类型：
--
作者：
Foessel, E.;Walter, J.;Barthes-Biesel, D.
数值研究了自由悬浮在简单剪切流中的弹性球壳的运动和变形，着重研究了内外粘度比的影响。三维流体与结构的相互作用通过边界积分法（用于内部和外部流体运动）与有限元法（用于膜变形）耦合来建模。对于低粘度比，内部粘度影响胶囊变形。相反，对于大的粘度比，内部运动的减速效应降低了整体胶囊变形;变形是渐近独立的流动强度和膜行为。一个重要的结果是，增加内部粘度导致膜压缩和可能的屈曲。在粘度比的临界值以上，对于所有流动强度，在胶囊膜上发现压缩区。这表明非常粘稠的胶囊易于弯曲。
The motion and deformation of a spherical elastic capsule freely suspended in a simple shear flow is studied numerically, focusing on the effect of the internal-to-external viscosity ratio. The three-dimensional fluid-structure interactions are modelled coupling a boundary integral method (for the internal and external fluid motion) with a finite element method (for the membrane deformation). For low viscosity ratios, the internal viscosity affect the capsule deformation. Conversely, for large viscosity ratios, the slowing effect of the internal motion lowers the overall capsule deformation; the deformation is asymptotically independent of the flow strength and membrane behaviour. An important result is that increasing the internal viscosity leads to membrane compression and possibly buckling. Above a critical value of the viscosity ratio, compression zones are found on the capsule membrane for all flow strengths. This shows that very viscous capsules tend to buckle easily.