Numerical Simulation of Blood Flow Fields in an Abdominal Aorta

• Main Authors: Chi-Yen Chen, 陳志彥
• Other Authors: Denz Lee
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/wsdg2h

博士 === 國立成功大學 === 航空太空工程學系碩博士班 === 90 === ABSTRACT Hemodynamic factors are thought to be responsible for the localization of vascular disease in areas of complex flow in the coronary, carotid, abdominal, and femoral arteries. In those regions, these complex flow often occur due to branching, bifurcation, and curvature of the arteries. Unlike other areas, the infrarenal aorta is much less investigated due to its complex geometry. In the present study, a reliable numerical simulation technique was developed to study the flow fields of flow in a multi-branched tube, especially, in a model of abdominal aorta. In order to solve the problems associated with complex geometry, a boundary-fitted coordinate system together with a zonal grid method is employed. The covariant physical velocity components are selected as the dependent variables in the momentum equations and a nonstaggered grid arrangement is employed. A grid generation procedure for branch tube was also developed. The basic flow patterns in T-junction were calculated firstly and the results were compared with the available experimental data. The flow field in a tube with two branches were then calculated to identify the interactions between the two branches. The flow field was found to be strongly affected by the distance of the two branches. Lastly, steady and pulsatile flow fields of an abdominal aorta with its main branches were simulated under both the resting and exercise conditions. The results showed that, in average, the regions of low/oscillating wall stress occurred on the infrarenal posterior wall of the abdominal aorta. Under the exercise conditions, these regions reduced significantly. The regions of low/oscillating wall shear stress on the lateral walls of iliac bifurcation persist under both conditions. These low/oscillating wall shear stress regions were consistent with the sites of vascular disease clinically.