Unsteady and three-dimensional simulation of blood flow in the human aortic arch
Unsteady and three-dimensional simulation of blood flow in the human aortic arch
复制标题
DOI：
10.1115/1.1487357
复制
发表时间：
2002-08-01
影响因子：
1.7
通讯作者：
Rutaganira, T
中科院分区：
文献类型：
--
作者：
Shahcheraghi, N;Dwyer, HA;Rutaganira, T
数值研究了峰值雷诺数为2500，频率参数为10的人体主动脉弓及其三个主要分支中的三维脉动血流。模拟几何是通过在人体主动脉上使用CAT扫描成像对一系列二维切片进行三维重建得到的。数值模拟采用投影法，采用有限体积格式的Navier-Stokes方程。我们的结果表明，升主动脉的一次血流速度偏向于主动脉内壁，而降主动脉的这种偏斜向外壁移动。在弓支内，血流速度向远端壁倾斜，近端壁血流逆转。在主动脉中观察到了广泛的二次流运动，这些二次流的结构受到分支的存在的很大影响。在主动脉内，壁面切应力是高度动态的，但在分支附近的外壁一般较高，而沿内壁的剪应力较低，尤其是在降主动脉。在分支内，远侧壁的剪应力明显高于近侧壁。升主动脉壁压力沿主动脉内壁较低，分支周围和外壁较高。我们的数值结果与早期动脉粥样硬化病变的定位比较广泛地表明，这些病变优先发展在壁切应力和压力的极端(或者最大或最小)区域。
A three-dimensional and pulsatile blood flow in a human aortic arch and its three major branches has been studied numerically for a peak Reynolds number of 2500 and a,frequency (or Womersley) parameter of 10. The simulation geometry was derived from the three-dimensional reconstruction of a series of two-dimensional slices obtained in vivo using CAT scan imaging on a human aorta. The numerical simulations were obtained using a projection method, and a finite-volume formulation of the Navier-Stokes equations was used on a system of overset grids. Our results demonstrate that the primary flow velocity is skewed towards the inner aortic wall in the ascending aorta, but this skewness shifts to the outer wall in the descending thoracic aorta. Within the arch branches, the flow velocities were skewed to the distal walls with flow reversal along the proximal walls. Extensive secondary flow motion was observed in the aorta, and the structure of these secondary flows was influenced considerably by the presence of the branches. Within the aorta, wall shear stresses were highly dynamic, but were generally high along the outer wall in the vicinity of the branches and low along the inner wall, particularly in the descending thoracic aorta. Within the branches, the shear stresses were considerably higher along the distal walls than along the proximal walls. Wall pressure was low along the inner aortic wall and high around the branches and along the outer wall in the ascending thoracic aorta. Comparison of our numerical results with the localization of early atherosclerotic lesions broadly suggests preferential development of these lesions in regions of extrema (either maxima or minima) in wall shear stress and pressure.