| Abstract | Platelets play an essential role in blood clotting; they adhere to damaged tissue and release chemicals that activate other platelets. Yet in order to adhere, platelets, which account for only 0.3% of the blood's volume, must first come into contact with the injured vessel wall. Fortunately, fluid dynamics have created a solution to this problem. Under arterial and arteriolar flow conditions, platelets have an enhanced concentration near blood vessel walls. This has been seen both in vitro and in vivo. This non-uniform cell distribution depends on the fluid dynamics of blood as a heterogeneous medium; no such effect occurs in a Newtonian fluid. Although lateral platelet motion has been well documented, the fluid dynamics are poorly understood. We use a parallelized lattice Boltzmann-immersed boundary method to solve the flow dynamics of red cells and platelets in a 2D vessel with no-slip boundary conditions. Red cells are treated as biconcave immersed boundary objects with isotropic Skalak membrane tension and an internal viscosity five times that of the surrounding plasma. Using this method we analyze the influence of shear rate, hematocrit and red cell membrane properties on lateral platelet motion. Insight gained from this work could lead to significant improvements to current models for platelet adhesion where the presence of red blood cells is neglected due to computational intensity. |
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