Flow of a spherical capsule in a pore with circular or square cross-section
Flow of a spherical capsule in a pore with circular or square cross-section
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DOI：
10.1017/jfm.2011.462
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发表时间：
2012-08-25
影响因子：
3.7
通讯作者：
Barthes-Biesel, D.
中科院分区：
文献类型：
--
作者：
Hu, X. -Q.;Salsac, A. -V.;Barthes-Biesel, D.
研究了在相当尺寸的孔隙中自由流动的球形弹性胶囊的运动和变形。薄胶囊膜具有新胡克剪切软化本构定律。通过将边界积分法（针对内部和外部流体运动）与有限元法（针对膜变形）相结合，对三维流体结构相互作用进行建模。在具有圆形横截面的圆柱形管中，通道壁的限制作用导致胶囊沿环向压缩。然后，如实验所观察到的，膜趋于弯曲和折叠。胶囊变形是三维的，但可以通过忽略折叠的轴对称模型很好地近似。在具有方形横截面的微流体孔中，胶囊变形是完全三维的。对于相同的尺寸比和流量，圆形截面孔中的胶囊比方形截面孔中的胶囊变形更大。我们提供了变形参数和胶囊速度作为方形截面孔隙中流动强度和尺寸比的函数的新图表。我们展示了如何使用这些图来分析此类通道中人造胶囊变形的实验数据。
The motion and deformation of a spherical elastic capsule freely flowing in a pore of comparable dimension is studied. The thin capsule membrane has a neo-Hookean shear softening constitutive law. The three-dimensional fluid structure interactions are modelled by coupling a boundary integral method (for the internal and external fluid motion) with a finite element method (for the membrane deformation). In a cylindrical tube with a circular cross-section, the confinement effect of the channel walls leads to compression of the capsule in the hoop direction. The membrane then tends to buckle and to fold as observed experimentally. The capsule deformation is three-dimensional but can be fairly well approximated by an axisymmetric model that ignores the folds. In a microfluidic pore with a square cross-section, the capsule deformation is fully three-dimensional. For the same size ratio and flow rate, a capsule is more deformed in a circular than in a square cross-section pore. We provide new graphs of the deformation parameters and capsule velocity as a function of flow strength and size ratio in a square section pore. We show how these graphs can be used to analyse experimental data on the deformation of artificial capsules in such channels.