Perktold K, Nerem R M, Peter R O
Institute of Mathematics, Technical University Graz, Austria.
J Biomech. 1991;24(3-4):175-89. doi: 10.1016/0021-9290(91)90176-n.
The flow pattern in the left main coronary artery has been calculated using an idealized geometry and by numerically solving the full Navier-Stokes equations for a Newtonian fluid. Two different forms for the entrance velocity profile were used, one a time-varying, flat profile and the other a time-varying, less flat velocity profile. The results obtained demonstrate the presence of secondary motions for conditions simulating flow in the left main coronary artery, with maximum secondary flow velocities being on the order of three to four percent of the maximum axial velocity. This secondary flow phenomenon has an important influence on the wall shear stress distribution, in spite of the fact that there is virtually no alteration in the axial velocity profile. The maximum ratio of the outer wall shear stress to that on the inner wall is 1.4 at a Reynolds number of Re = 270, and it increases with increasing Reynolds number, reaching a value of 1.7 at Re = 810. Although there are significant differences in the results in the immediate vicinity of the inlet for the two different forms of the entrance velocity profile used, this difference does not persist far into the tube. Independent of the choice of the entrance velocity profile, it appears that there will be significant secondary flow effects on the wall shear stress.
利用理想化几何结构并通过数值求解牛顿流体的完整纳维-斯托克斯方程，计算了左冠状动脉主干中的血流模式。使用了两种不同形式的入口速度剖面，一种是随时间变化的平坦剖面，另一种是随时间变化的不太平坦的速度剖面。所得结果表明，在模拟左冠状动脉主干血流的条件下存在二次流动，最大二次流速约为最大轴向流速的3%至4%。尽管轴向速度剖面几乎没有变化，但这种二次流动现象对壁面剪应力分布有重要影响。在外壁剪应力与内壁剪应力的最大比值在雷诺数Re = 270时为1.4，并且随着雷诺数的增加而增大，在Re = 810时达到1.7。尽管对于所使用的两种不同形式的入口速度剖面，在入口紧邻区域的结果存在显著差异，但这种差异在管内不会持续很远。无论入口速度剖面如何选择，似乎二次流动对壁面剪应力都会有显著影响。
