COMPUTATIONAL FLOW VISUALIZATION IN AN AORTIC ANEURYSM

Abstract

Atherosclerosis and atherosclerotic aneurysms can occur in the abdominal aorta. Steady and pulsatile three-dimensional flow cases were simulated in an abdominal aortic aneurysm on a graphics workstation. In the steady flow case, in the aneurysm center, two symmetric vortices were formed, and flow separation started at the aneurysm inlet. Regions of high pressure were observed at the aneurysm exit caused by the symmetric jets that were formed, implying that this high-pressure region could be an area where rupture is most likely. The shear stress was low in the aneurysm portion of the vessel, and local maximum values were observed at the distal aneurysm constriction. In the unsteady flow case, the main vortex appeared and disappeared and changed position in the unsteady flow case and induced vortices were formed; in the steady flow case only one constant vortex was observed in the centerline view. The graphics system allows instant observation of the vascular structures from any angle or distance while moving, with wire frame and solid viewing modes being possible. The graphics programs allow the viewer to travel inside the aneurysm to observe the pressure and shear distribution in colorful detail, and videos have been made.