Key result
Non-Newtonian fluid models demonstrated shorter flow separation duration and weaker reverse flow compared to Newtonian models, with potential effects on wall shear stress magnitude.
CFD modeling of arterial bifurcations demonstrates the importance of accounting for non-Newtonian viscosity in regions of flow separation and wall shear stress.
May refine CFD wall shear stress estimates in bifurcations; hypothesis-generating for non-Newtonian modeling, needs human validation.
The local blood flow in arteries, especially at bends and bifurcations, is correlated with the distribution of atherosclerotic lesions. The flow is three-dimensional, unsteady and difficult to measure in vivo. In this paper a numerical treatment of blood flow in general three-dimensional arterial bifurcations is presented. The flow is assumed to be laminar and incompressible, the blood non-Newtonian and the vessel wall rigid. The three-dimensional time-dependent Navier-Stokes equations are employed to describe the flow, and a newly developed computational fluid dynamics (CFD) code AST EC based on finite volume methods is used to solve the equations. A comprehensive range of code validations has been carried out. Good agreement between numerical predictions and in vitro model data is demonstrated, but the correlation with in vivo measurements is less satisfactory. Effects of the non-Newtonian viscosity have also been investigated. It is demonstrated that differences between Newtonian and non-Newtonian flows occur mainly in regions of flow separation. With the non-Newtonian fluid, the duration of flow separation is shorter and the reverse flow is weaker. Nevertheless, it does not have significant effects on the basic features of the flow field. As for the magnitude of wall shear stress, the effect of non-Newtonian viscosity might not be negligible.
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Xu et al. (1994) studied Atherosclerosis (arterial bifurcations). Non-Newtonian fluid model vs. Newtonian fluid model was evaluated on Flow separation and wall shear stress. Non-Newtonian fluid models demonstrated shorter flow separation duration and weaker reverse flow compared to Newtonian models, with potential effects on wall shear stress magnitude.
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