论文标题

理想化的弯曲动脉中生理流动发育对流行壁剪应力指标的影响

The influence of physiological flow development on popular wall shear stress metrics in an idealized curved artery

论文作者

Cox, Christopher, Plesniak, Michael W.

论文摘要

我们从数值上研究了流动发展对弯曲动脉模型中二级流动模式和随后的壁剪应力分布的影响,并计算出通常用于评估血液流量特征变化的血管指标,因为它适用于动脉疾病。我们对人动脉进行建模,具有简单,刚性的180度弯曲管,具有圆形横截面和恒定曲率,逐渐忽略的锥度,扭转和弹性的效果。高保真数值结果是从内部不连续的光谱元件流量求解器计算的。这项研究中使用的流速是生理的。我们使用牛顿血脉液体进行脉动流动,并使用两个流入条件进行脉动流动进行这项研究。第一个流条件是完全发展的,而第二条件不发达(即均匀)。我们观察和讨论在生理波形的快速加速和减速阶段中出现的二次流动模式的差异,我们直接将这些次级流模式的强度变化与每个入口条件的壁剪应力指标的差异联系在一起。结果表明,在未开发状态下轴向速度的降低会产生较不强度的二次流,从而降低了壁剪应力载体的振荡性和多向性质,我们将这种效应与计算的应力指标的异常联系起来。这些结果表明,在弯曲流动相当不发达的曲率中,疾病的患病率可能降低,这在生理上相关的结果是进一步了解血流发展对疾病的影响。

We numerically investigate the influence of flow development on secondary flow patterns and subsequent wall shear stress distributions in a curved artery model, and we compute vascular metrics commonly used to assess variations in blood flow characteristics as it applies to arterial disease. We model a human artery with a simple, rigid 180-degree curved tube with circular cross-section and constant curvature, neglecting effects of taper, torsion and elasticity. High-fidelity numerical results are computed from an in-house discontinuous spectral element flow solver. The flow rate used in this study is physiological. We perform this study using a Newtonian blood-analog fluid subjected to a pulsatile flow with two inflow conditions. The first flow condition is fully developed while the second condition is undeveloped (i.e. uniform). We observe and discuss differences in secondary flow patterns that emerge over the rapid acceleration and deceleration phases of the physiological waveform, and we directly connect the variation in intensity of these secondary flow patterns along the curvature to differences in the wall shear stress metrics for each entrance condition. Results indicate that decreased axial velocities under an undeveloped condition produce less intense secondary flow that, in turn, reduces both the oscillatory and multidirectional nature of the wall shear stress vector, and we link this effect to abnormalities in computed stress metrics. These results suggest potentially lower prevalence of disease in curvatures where entrance flow is rather undeveloped-a physiologically relevant result to further understand the influence of blood flow development on disease.

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