Zhao Y, Sharp M K
Department of Civil and Environmental Engineering, University of Utah, Salt Lake City 84112, USA.
J Biomech Eng. 1999 Apr;121(2):148-52. doi: 10.1115/1.2835096.
Motivated by the lateral migration phenomena of fresh and glutaraldehyde-fixed red blood cells in a field flow fractionation (FFF) separation system, we studied the transverse hydrodynamic lift on a slightly flexible cylinder in a two-dimensional channel flow. The finite element method was used to analyze the flow field with the cylinder at different transverse locations in the channel. The shape of the cylinder was determined by the pressure on the surface of the cylinder from the flow field solution and by the internal elastic stress. The cylinder deformation and the flow field were solved simultaneously. The transverse lift exerted on the cylinder was then calculated. The axial and angular speed of the cylinder were iterated such that the drag and torque on the cylinder were nulled to represent a freely translating and rotating state. The results showed that the transverse lift on a deformable cylinder increased greatly and the equilibrium position moved closer to the center of the channel compared to a rigid cylinder. Also, with the same elastic modulus but a higher flow rate, a larger deformation and higher equilibrium location were found. The maximum deformation of the cylinder occurred when the cylinder was closest to the wall where a larger shear rate existed. The numerical results and experimental studies are discussed.
受场流分级（FFF）分离系统中新鲜和戊二醛固定红细胞横向迁移现象的启发，我们研究了二维通道流中微柔性圆柱体上的横向流体动力升力。采用有限元方法分析了圆柱体在通道中不同横向位置时的流场。圆柱体的形状由流场解中圆柱体表面的压力以及内部弹性应力确定。同时求解圆柱体变形和流场。然后计算作用在圆柱体上的横向升力。迭代圆柱体的轴向和角速度，使圆柱体上的阻力和扭矩为零，以表示自由平移和旋转状态。结果表明，与刚性圆柱体相比，可变形圆柱体上的横向升力大幅增加，平衡位置向通道中心靠近。此外，在相同弹性模量但流速较高的情况下，发现变形更大且平衡位置更高。圆柱体的最大变形发生在其最靠近存在较大剪切速率的壁面处。对数值结果和实验研究进行了讨论。
