Blood viscosity and optimal hematocrit in narrow tubes

Pulsatile flow in a coronary artery using multiphase kinetic theory

“…The existence of cell depletion and shear thinning has been determined experimentally for straight narrow tubes (Reinke et al, 1987;Stadler et al, 1990;Haynes, 1960). In recent years, single-phase computational fluid dynamics (CFD) techniques, combined with noninvasive medical imaging, have been used increasingly by researchers seeking to better understand hemodynamic factors (Berthier et al, 2002;Steinman, 2002;Zeng et al, 2003;Gijsen et al, 1999;He and Ku, 1996;Hoi et al, 2004;Santamarina et al, 1998;Boutsianis et al, 2004;Politis et al, 2007Politis et al, , 2008.…”

Stochastic finite difference lattice Boltzmann method for steady incompressible viscous flows

“…Blood viscosity is made up of two parts; one is due to the liquid-content and the other is due to the Hct content [20][21][22]. The viscosity of the liquid-content part remains relatively constant even if there are changes in shear rate, velocity and pressure.…”

“…Its viscosity is affected by a number of factors; chief among them is the macromolecular component hematocrit (Hct). In addition, it is also influenced by the pressure, velocity, and the local shear rate of the flow [20][21][22]. Cholesterol and/or plaque buildup inside arteries changes the geometry of the blood vessel and in turn the pressure, velocity, and the local shear rate [23].…”

“…The immersed boundary method can also be incorporated into the SFDLBM through an additional distribution function in the modeled lattice Boltzmann equation; this task will be carried out later. Since blood viscosity l is influenced by changing velocity, pressure, and shear rate [20][21][22], it could be argued that l might vary substantially in the region where these changes occur. Therefore, in the constricted section, l will not only be affected by the changing velocity, pressure, and shear rate, it might also loss its spatially uniform property.…”

Kinetic Theory Based Model for Blood Flow and its Viscosity

“…Since Fahraeus and Lindqvist 11 first observed the significant decrease of apparent blood viscosity as the vessel diameter decreases, many investigators confirmed this effect through vitro experiments. 5,20,41 Since the invention of the microscope it was suspected that red blood cells (RBCs) in small blood vessels migrate away from the wall. The formation of a cell-free layer near the wall reduces the apparent blood viscosity and hence the pressure-drop through the narrow blood vessels.…”