Dynamic Response of a Red Blood Cell in Shear Flow

Three-dimensional simulation of a red blood cell deformation in a shear flow is performed using immersed boundary lattice Boltzmann method for the fluid flow simulation, as well as finite element method for membrane deformation. Immersed boundary method has been used to model interaction between fluid and membrane of the red blood cell. Red blood cell is modeled as a biconcave discoid capsule containing fluid with an elastic membrane. Computations are performed at relatively small and large shear rates in order to study the dynamic behavior of red blood cell, especially tumbling and swinging modes of its motion. A rigid-body-like motion with the constant-amplitude oscillation of deformation parameter and continuous rotation is observed for red blood cell at its tumbling mode. However, at a relatively large shear rate, red blood cell follows a periodic gradual deformation and elongation with a final ellipsoidal shape. The effect of different initial orientations of red blood cell is also investigated in the present paper. Results show that the dynamic response of red blood cell is not sensitive to this parameter.