Numerical simulation of pulsatile non-Newtonian flow in the carotid artery bifurcation |
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Authors: | Yubo Fan Wentao Jiang Yuanwen Zou Jinchuan Li Junkai Chen Xiaoyan Deng |
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Institution: | (1) School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, China;(2) Biomechanical Engineering Laboratory, Sichuan University, 610065 Chengdu, China |
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Abstract: | Both clinical and post mortem studies indicate that, in humans, the carotid sinus of the carotid artery bifurcation is one
of the favored sites for the genesis and development of atherosclerotic lesions. Hemodynamic factors have been suggested to
be important in atherogenesis. To understand the correlation between atherogenesis and fluid dynamics in the carotid sinus,
the blood flow in artery was simulated numerically. In those studies, the property of blood was treated as an incompressible,
Newtonian fluid. In fact, however, the blood is a complicated non-Newtonian fluid with shear thinning and viscoelastic properties,
especially when the shear rate is low. A variety of non-Newtonian models have been applied in the numerical studies. Among
them, the Casson equation was widely used. However, the Casson equation agrees well only when the shear rate is less than
10 s−1. The flow field of the carotid bifurcation usually covers a wide range of shear rate. We therefore believe that it may not
be sufficient to describe the property of blood only using the Casson equation in the whole flow field of the carotid bifurcation.
In the present study, three different blood constitutive models, namely, the Newtonian, the Casson and the hybrid fluid constitutive
models were used in the flow simulation of the human carotid bifurcation. The results were compared among the three models.
The results showed that the Newtonian model and the hybrid model had very similar distributions of the axial velocity, secondary
flow and wall shear stress, but the Casson model resulted in significant differences in these distributions from the other
two models. This study suggests that it is not appropriate to only use the Casson equation to simulate the whole flow field
of the carotid bifurcation, and on the other hand, Newtonian fluid is a good approximation to blood for flow simulations in
the carotid artery bifurcation.
This project was supported by the National Natural Science Foundation of China (10527001, 10632010, 10672015). |
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Keywords: | Casson equation Hybrid fluid Newtonian fluid Carotid artery bifurcation |
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