二维细胞在剪切流中的运动特性

Modeling two-dimensional cell deformation in shear flow

主要模拟二维细胞在剪切流中的运动特性。计算过程采用浸入边界法,将细胞模化成Navier-Stokes方程中的力源,而不是真实物体。假设细胞的初始形状为椭圆,细胞内外流体粘性相同,细胞膜的弹性力模型选用E-S模型。本文模拟四种不同真圆度情况下细胞的形变情况,观测到初始阶段细胞沿着长轴方向做拉伸和旋转运动,达到稳定状态后细胞作类坦克履带式运动;并且发现细胞达到稳定状态所需要的时间随真圆度的增加而增加,而细胞的稳态倾角随真圆度的增加而减少。

The deformation of two-dimensional cell in shear flow is investigated. The immersed boundary method, where the immersed boundary is modeled as a force source instead of a read body, is utilized to simulate the cell motion. An elliptical shape is taken as the initial shape of the cell. The Evans-Skalas elasticity law is chosen for the description of the membrane mechanics and it is assumed that the viscosity ratio between the interior and exterior fluids of the cell is unity. Several cases for different circularities are simulated to study the deformation of the cell. It is observed that the cell elongates along the long axis as well as rotates round the origin first and the tank-treading motion begins when the cell reaches its steady state. It is also found out that as the circularity increases, the inclination of the cell at steady state decreases and the time required to reach the steady state increases.