頸動脈分岐部での流れの数値解析 : 分岐部幾何形状・流量比とWSS分布との関係(流体工学,流体機械)  [in Japanese] Computational Study of Flow in a Carotid Bifurcation : Geometry and Flow Ratio Correlations with WSS(Fluids Engineering)  [in Japanese]

The present study presents a three-dimensional steady numerical simulation of flow through a model of the bifurcation of the common carotid artery (CCA) into the internal (ICA) and external carotid (EGA) arteries. Flow with large inertia bifurcates at the apex (divider tip) and creates a flow recirculation zone associating with very low wall shear stress (WSS) at the outer wall of the ICA sinus where atherosclerotic plaques are localized. The change of both the CCA-ICA and CCA-EGA bifurcation angle has more effect on the distribution of WSS over the outer wall of the sinus. A larger angle of daughter tubes makes the region of low WSS in the ICA sinus narrower in the flow direction, however, makes the WSS gradient in regions surrounding the ICA sinus steeper for a higher volumetric flow ratio of the ICA : EGA. In contrast to the WSS features, the distribution of the axial flow velocity in the plane of symmetry is not very sensitive to the change in both the bifurcation angle and flow ratio between the ICA and ECA.