A Sharp-Interface Fluid-Structure Interaction Algorithm for Modeling Red Blood Cells

RBC deformation is thought to play a major role in both RBC dynamics and functionality. Due to the difficulty of experiments on real RBCs, researchers tend to perform computational simulations that can cover RBC dynamics and blood rheology. However, modeling of RBC with physiological conditions is still not completely well established. The current work utilized the immersed interface method and implements the fluid structure interaction technique to propose a new computational model of RBC as a biconcave fluid-filled cell. RBC is presented by a two dimensional hyperelastic massless membrane that surrounded by plasma and enclosed hemoglobin. The physiological viscosity ratio for the hemoglobin to that of plasma and their interactions with the cell membrane is considered. Pressure and velocity jump conditions are applied at the membrane, so that the influence of extracellular fluid can be transferred to the intracellular fluid. The model was applied to study the deformation of a single RBC as it flows in straight channels with geometries similar to that could find in capillaries with low Reynolds numbers that vary from 0.001 to 0.01. As Reynolds number increases, RBC shows higher levels of deformation. Flow fields through the cell membrane are appeared to be different and jumps in both velocity and pressure can be clearly seen