LoGerfo F W, Crawshaw H M, Nowak M, Serrallach E, Quist W C, Valeri C R
Stroke. 1981 Sep-Oct;12(5):660-5. doi: 10.1161/01.str.12.5.660.
This is a study of the flow disturbance in a plastic model of an asymmetric vascular bifurcation. A sidearm was attached to the mainlimb at an angle of 15 degrees to the inlet flow axis. Water at steady flow was used and flow patterns were demonstrated by a dye injection technique. The proportion of inlet flow (Qi) exiting from the sidearm (Qs) was varied and flow patterns were recorded photographically. A laser Doppler anemometer (LDA) was used to measure near-wall velocity. At a physiologic Reynolds' number of 500, no flow disturbance occurred in the mainlimb when the sidearm was completely occluded. When the fraction of flow exiting from the sidearm (Qs/Qi) reached 0.19, a region of boundary layer separation developed along the wall of the mainlimb opposite the flow divider. This region of nearly static fluid spread circumferentially around the mainlimb as Qs/Qi increased. Near-wall velocity within the separation decreased and became negative when Qs/Qi = 0.31. When Qs/Qi reached 0.38, the separation enveloped the wall of the entire bifurcation with a shell of slowly moving fluid. At the same time, the rapidly moving mainstream impinged directly on the flow divider. There is a similarity between the region of separation seen in this model and the site of formation of atherosclerotic plaque at the carotid bifurcation. Separation may contribute to atherogenesis by creating a region of low wall shear at bifurcations.
这是一项关于非对称血管分叉塑料模型中血流扰动的研究。一个侧支以与入口血流轴呈15度角的方式连接到主支上。使用稳定水流，并通过染料注射技术展示血流模式。改变从侧支流出的入口血流（Qi）比例（Qs），并用摄影记录血流模式。使用激光多普勒测速仪（LDA）测量近壁速度。在生理雷诺数为500时，当侧支完全闭塞时主支中未发生血流扰动。当从侧支流出的血流比例（Qs/Qi）达到0.19时，在主支中与分流器相对的壁面处形成了一个边界层分离区域。随着Qs/Qi增加，这个几乎静止的流体区域沿主支周向扩展。当Qs/Qi = 0.31时，分离区域内的近壁速度降低并变为负值。当Qs/Qi达到0.38时，分离区域包裹了整个分叉的壁面，形成一层缓慢流动的流体壳。与此同时，快速流动的主流直接冲击分流器。该模型中观察到的分离区域与颈动脉分叉处动脉粥样硬化斑块形成部位之间存在相似性。分离可能通过在分叉处形成低壁面切应力区域而促进动脉粥样硬化的发生。
