Shape oscillations of elastic particles in shear flow.
Shape oscillations of elastic particles in shear flow.
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DOI：
10.1016/j.jmbbm.2016.05.031
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发表时间：
2016-09
影响因子：
3.9
通讯作者：
D. Subramaniam;D. Gee
中科院分区：
文献类型：
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作者：
D. Subramaniam;D. Gee
颗粒悬浮液对于生物流体流动是常见的;例如，红细胞和白细胞以及血小板的流动。在医疗技术中，目前和提出的药物递送方法使用膜结合的液体胶囊通过微循环进行运输。在本文中，我们考虑了一个三维线弹性粒子插入到牛顿流体和调查的时间依赖性变形使用的数值模拟。具体而言，边界元技术被用来调查的运动和变形的初始球形或类球形颗粒在有界线性剪切流。由此产生的变形的形状揭示了一个稳态的配置文件，表现出一个“坦克踩”的运动，最初的球形颗粒。壁对颗粒轨迹的影响被认为包括修改后的杰弗里的球形夹杂物的轨道与剪切流的强度成反比变化的周期。或者，球状夹杂物可以表现出“翻滚”或“颤抖”运动，这取决于初始颗粒纵横比和毛细管数（即，流体剪切力与弹性恢复力之比）。我们发现对于0.1的毛细管数，翻滚模式在0.87（近似）的纵横比处转变为抖动模式，而对于0.2的毛细管数，这种转变发生在较低的纵横比。这些振荡模式与涉及类似形状的囊泡的实验观察是一致的，因此用于验证使用一个简单的弹性本构模型来执行相关的生理流量计算。
Particle suspensions are common to biological fluid flows; for example, flow of red- and white-blood cells, and platelets. In medical technology, current and proposed methods for drug delivery use membrane-bounded liquid capsules for transport via the microcirculation. In this paper, we consider a 3D linear elastic particle inserted into a Newtonian fluid and investigate the time-dependent deformation using a numerical simulation. Specifically, a boundary element technique is used to investigate the motion and deformation of initially spherical or spheroidal particles in bounded linear shear flow. The resulting deformed shapes reveal a steady-state profile that exhibits a ‘tank-treading’ motion for initially spherical particles. Wall effects on particle trajectory are seen to include a modified Jeffrey׳s orbit for spheroidal inclusions with a period that varies inversely with the strength of the shear flow. Alternately, spheroidal inclusions may exhibit either a ‘tumbling’ or ‘trembling’ motion depending on the initial particle aspect ratio and the capillary number (i.e., ratio of fluid shear to elastic restoring force). We find for a capillary number of 0.1, a tumbling mode transitions to a trembling mode at an aspect ratio of 0.87 (approx.), while for a capillary number of 0.2, this transition takes place at a lower aspect ratio. These oscillatory modes are consistent with experimental observations involving similarly shaped vesicles and thus serves to validate the use of a simple elastic constitutive model to perform relevant physiological flow calculations.