Perktold K, Hofer M, Rappitsch G, Loew M, Kuban B D, Friedman M H
Institute of Mathematics, Technical University Graz, Austria.
J Biomech. 1998 Mar;31(3):217-28. doi: 10.1016/s0021-9290(97)00118-8.
The pulsatile flow field in an anatomically realistic model of the bifurcation of the left anterior descending coronary artery (LAD) and its first diagonal branch (D1) was simulated numerically and measured by laser Doppler anemometry. The inlet velocity profiles used in the computer simulation and in the physical experiments were physiologically realistic. The computational geometric model was developed on the basis of a digitized arterial cast. The curvature of the LAD over the cardiac surface leads to axial velocity profiles which are slightly skewed towards the epicardial wall. Downstream of the bifurcation, a strong skewing occurs towards the flow divider walls as a result of branching. Locally, the wall shear stress component caused by the complex secondary velocity can be as high as the axial component. The wall shear stress representation from a cell-based perspective exhibits low shear stress and large deviation from the time-averaged shear stress direction during systole. In diastole, the instantaneous wall shear stress direction nearly corresponds to the mean direction. The comparison of computed and measured axial velocity results shows generally good agreement. In contrast to computed flow patterns in simpler geometries constructed from cylindrical tubes, the flow field is found to be smoother, presumably reflecting the adaptation of the vascular contour to the contained flow.
在一个解剖学上逼真的左前降支冠状动脉（LAD）及其第一对角支（D1）分叉模型中，对脉动流场进行了数值模拟，并通过激光多普勒测速仪进行了测量。计算机模拟和物理实验中使用的入口速度剖面在生理上是逼真的。计算几何模型是在数字化动脉铸型的基础上开发的。LAD在心脏表面的曲率导致轴向速度剖面略微偏向心外膜壁。在分叉下游，由于分支，流向分流壁的强烈偏斜出现。局部地，由复杂二次速度引起的壁面剪应力分量可高达轴向分量。从基于单元的角度来看，壁面剪应力表示在收缩期呈现出低剪应力，并且与时间平均剪应力方向存在较大偏差。在舒张期，瞬时壁面剪应力方向几乎与平均方向一致。计算结果与测量的轴向速度结果的比较总体上显示出良好的一致性。与由圆柱管构建的更简单几何形状中的计算流型相比，发现流场更平滑，可以推测这反映了血管轮廓对所含血流的适应性。
