Flow Structure Through Confluent and Bifurcating Channel in Laminar Steady Flow

The aneurysm in the cerebral artery is apt to generate along the “Circle of Willis.” The anterior communicating artery, which composes one part of the circle of Willis, is one of the most predilection regions of the aneurysm. This artery is characterized by a singular geometry. Namely, two confluent vessels (proximal anterior cerebral artery) join facing each other at the junction which is the anterior communicating artery. Just at this junction, the flow bifurcates two vessels (distal anterior cerebral artery). Therefore, the flow around the junction, i.e., anterior communicating artery, would be very unstable. The aneurysm arises around the apex of the junction where the confluent flow collides.