Lattice Boltzmann simulation of motion of red blood cell in constricted circular pipe flow

The lattice Boltzmann method for two-phase flows containing a deformable body with a viscoelastic membrane is improved to simulate circular pipe flows by incorporation of the immersed boundary method. In order to examine the validity of the red blood cell (RBC) model, the method is applied to the motion of a biconcave disk-shaped body in a pressure-driven circular pipe flow. The validation is demonstrated by investigating the relation between the deformation index and terminal axial velocity of the RBC in the pipe flow. In this study, the behavior of a biconcave disk-shaped body in constricted pipe flows is simulated under various geometrical conditions. The square and circular pipes with various lengths and sizes of the constriction are considered, and the flow is induced by the pressure difference between the inlet and outlet. From the results, it is found that as the length of the constriction becomes smaller, the body is deformed larger and accelerated at the entrance and exit in the constriction, although the speed of the body is reduced while passing through the constriction. Also, it is found that as the size of the constriction becomes larger, the deformation index linearly decreases and the axial velocity exponentially increases. These results indicate that the present method has applicability to simulation of the motion of RBCs in microscale capillary blood vessels.ArticleJournal of Fluid Science and Technology.9(3):JFST0031(2014)journal articl