Non-Newtonian blood flow modeling in healthy and atherosclerotic carotid arteries and hyperelastic CSS modeling

To date many studies have been done on the concept of development of atherosclerosis and specifically on the role of local hemodynamic. This disease is considered as a major cause of stroke. Local hemodynamic and vessel wall behavior are the factors that are put forward as major causes of formation of atherosclerosis in literature. Among hemodynamic factors, the Wall Shear Stress (WSS) seems to be corresponding to wall thickening and also formation of the disease more than any other factor. Due to importance of WSS in formation of arterial diseases, the Carreau-Yasuda non- Newtonian model was chosen to describe the mechanical behavior of blood in this study. This study aims to use non invasive methods to investigate the detailed flow in geometries extracted from in vivo data. The studied geometries are reconstructed by the use ofCT scan data. This method is applied on one healthy, two diseased with different percentage in occlusion, and an ideal carotid bifurcation. In addition the role of elasticity and mechanical behavior of the vessel wall is discussed by applying the results of numerical solution of fluid domain of an ideal carotid on solid domain. The CSS-modeling or cyclic strain simulation was used to investigate the effects of mechanical behavior of vessel wall in critical zones. Results show a significant and uprising change in 3D velocity profile and distribution of WSS with respect to percentage of occlusion and show how significantly the use of real geometry could change the results. The regions with small reverse flow area and low WSS in downstream of the flow are indicated, compared and further studied.

Keywords:

CFD , patient-based , CT scan , cyclic strain , WSS