Mesoscopic Blood Flow Simulation Considering Hematocrit-Dependent Viscosity

概要

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Blood is a concentrated suspension of blood cells in plasma. Motion and deformation of red blood cells (RBCs) and their mechanical interaction play important roles in determining blood rheology. Here, we propose a computational model of mesoscopic blood flow where the particulate and continuum natures of blood coexist. We modeled blood flow at two different scales, RBC flow at the microscopic level and continuum at the macroscopic level. A hematocrit-dependent viscosity was considered to take account of the effects of the spatial variation of RBC concentrations on the macroscopic flow. Starting with a Poiseuille flow, the blood flow in a cylindrical channel was simulated. Due to fluid shears, RBCs migrated radially toward the center of flow channel, causing a higher fluid viscosity around the central axis than that near the wall of the channel. Such a spatial variation in viscosity altered the velocity profile of macroscopic blood flow and further changed the RBC distribution within the channel. An iterative calculation resulted in a decrease in flow velocity at the center of the flow channel, as observed in vivo and in vitro. These results address the potential of the present computational approach in the analysis of mesoscopic blood flow.