This study aims to investigate the elastic properties of blood for pulsatile arterial hemodynamics in terms of their effects on velocity, vorticity and stress fields, as well as the aneurysm rupture risk indicators. The blood flow in a developed fusiform aneurysm is numerically simulated using the modified Oldroyd–B viscoelastic fluid model which includes shear thinning effects, and the results are compared with Newtonian and purely shear thinning Carreau model predictions. Fluid-solid interaction method with arbitrary Lagrangian–Eulerian formulation is adopted in the simulations, where the arterial wall is modeled as a linearly elastic material. The viscoelastic fluid displays significant differences in the vortical field, where the rotation direction of the vortices is reversed, and additional secondary and tertiary vortices appear. The effects of increasing fluid elasticity on hemodynamics are further investigated comparing large and medium vessel geometries. As inertia is decreased viscoelastic effects become more pronounced for the medium artery model, and the difference in the velocity and vortical fields between the Newtonian and Carreau models are reduced, due to the decrease in shear thinning effects. For the modified Oldroyd–B model, an increase in the fluid's elasticity level, observed through the medium artery model, affects the vortical fields as the primary vortex grows and shifts towards the distal end, and the risk indicators increase compared to the large artery geometry and inelastic rheological models. Along the interface at the vessel wall, von Mises stresses are also observed to increase with fluid's elasticity. It is also shown that the hyperelastic vessel wall assumption leads to small differences in the flow structure and the risk indicators with respect to the linearly elastic vessel wall case for the modified Oldroyd–B model.

这项研究旨在研究血液对搏动性动脉血流动力学的弹性特性，包括其对速度，涡度和应力场的影响，以及动脉瘤破裂的风险指标。使用修正的Oldroyd-B粘弹性流体模型（包括剪切稀化效应）对发达的梭状动脉瘤中的血流进行了数值模拟，并将结果与​​牛顿模型和纯剪切稀化Carreau模型的预测进行了比较。在模拟中采用具有任意拉格朗日-欧拉公式的流固耦合方法，其中动脉壁被建模为线性弹性材料。粘弹性流体在涡旋场中显示出显着差异，在这种情况下，涡旋的旋转方向相反，并且还会出现其他的二级和三级涡旋。比较大中型血管的几何形状，进一步研究了增加流体弹性对血液动力学的影响。随着惯性的减小，对于中等动脉模型，粘弹性效应变得更加明显，并且由于剪切稀化效应的减小，牛顿模型和Carreau模型之间的速度场和涡旋场差异也减小了。对于改良的Oldroyd–B模型，通过中动脉模型观察到的流体弹性水平的增加会随着初级涡旋的增长和向远端的移动而影响涡旋场，并且与大动脉几何体相比，风险指标会增加和非弹性流变模型。沿着血管壁的界面，还观察到冯·米塞斯（von Mises）应力随着流体的弹性而增加。