Secondary flow structures under stent-induced perturbations for cardiovascular flow in a curved artery model

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• 作者：Autumn L. Glenn^a ; Kartik V. Bulusu^a ; Fangjun Shu^b ; Michael W. Plesniak^a ; ^{plesniak@gwu.edu}
• 关键词：Secondary flow ; Regime map ; Stent ; Instability ; Secondary streaming Reynolds number
• 刊名：International Journal of Heat and Fluid Flow
• 出版年：2012
• 期刊代码：80_0142727x
• 类别：et
• 出版时间：June, 2012
• 卷：35
• 期：Complete
• 页码：76-83
• 文件大小：1608 K

摘要

Secondary flows within curved arteries with unsteady forcing result from amplified centrifugal instabilities and are expected to be driven by the rapid accelerations and decelerations inherent in physiological waveforms. These secondary flows may also affect the function of curved arteries through pro-atherogenic wall shear stresses, platelet residence time and other vascular response mechanisms.

Planar PIV measurements were performed under multi-harmonic non-zero-mean and physiological carotid artery waveforms at various locations in a rigid bent-pipe curved artery model. Results revealed symmetric counter-rotating vortex pairs that developed during the acceleration phases of both multi-harmonic and physiological waveforms. An idealized stent model was placed upstream of the bend, which initiated flow perturbations under physiological inflow conditions. Changes in the secondary flow structures were observed during the systolic deceleration phase (t/T 鈮?#xA0;0.20-0.50). Proper Orthogonal Decomposition (POD) analysis of the flow morphologies under unsteady conditions indicated similarities in the coherent secondary-flow structures and correlation with phase-averaged velocity fields.

A regime map was created that characterizes the kaleidoscope of vortical secondary flows with multiple vortex pairs and interesting secondary flow morphologies. This regime map in the curved artery model was created by plotting the secondary Reynolds number against another dimensionless acceleration-based parameter marking numbered regions of vortex pairs.