Int J Biol Sci 2013; 9(10):1050-1056. doi:10.7150/ijbs.7242 This issue
Department of Mechanics and Engineering Science, Fudan University, Shanghai Research Center of Acupuncture, Shanghai, 200433.
In this paper, we use Stokes, Brinkman and Darcy equations to approximate the porous continuum media of ligament tissues respectively, simulate the flow field with FLUENT software, and study the shear stress on the cell surface due to the interstitial fluid flow. Since the Brinkman equation approaches Stokes equation well in high hydraulic permeability (kp) condition (kp ≥1.0×10-8 m2 in our numerical simulation), and it is an approximation to Darcy model in low kp condition (kp ≤5.0×10-12 m2 in our numerical simulation), we used the Brinkman model to simulate the interstitial fluid flow in the ligament where kp is approximately 1.0×10-16 m2. It shows kp and anisotropic property have a little effect on the flow field, but have a great effect on the shear stress on the membrane of interstitial cells (τcell). There is a linear relationship between τcell and , when kp =1.0×10-16 m2 and the maximum τcell (τcell,max) is approximately 10 Pa. The anisotropic property will affect τcell's distribution on the cell surface. When kx/ky>1, low τcell dominates the cell, while when kx/ky<1, high τcell dominants the cell.
Keywords: Interstitial fluid flow, porous media, numerical simulation, sheer stress, anisotropy.