Numerical modeling of the fluid-structure interaction during blood flow in a flexible stenotic aorta

The aim of this study is to understand the relationship between blood flow and vascular mechanics in stenotic and healthy arteries and use this understanding to improve the accuracy of computational models for predicting blood flow in human arteries. The article considers four models: a flexible and rigid model of a healthy artery and two flexible arteries with stenoses of various shapes. The deformation of a blood vessel is modeled as a fluidstructure interaction (FSI). The arterial wall is modeled as an isotropic, linearly elastic material, and wall shear stress (WSS) is calculated in order to explore the correlation between induced flow stress and the shape of the artery geometry. Blood is considered as an incompressible non-Newtonian fluid, described by the Carreau viscosity model. Signals of physiological pressure and velocity are used as boundary conditions, which ensure the pulsating nature of the flow. Numerical results show that the developed model predicts vessel deformations and describes their influence on pressure distribution, pressure drop and wall shear stresses. The results of the healthy FSI model are compared with the results of the rigid wall model in order to evaluate the effect of wall elasticity on wall shear stress distribution. Thus, under pathological conditions, the maximum speed value was observed in the model with 40% stenosis and reached 2.16 m/s, while the model with 30% stenosis had a speed of 2.06 m/s. In this case, the maximum displacement of the walls during the cardiac cycle was observed in the artery with 40% stenosis. The deformation value exceeded the wall thickness by 3.3 times and reached 1.66 mm.