Artery curvatures, where disturbed flow patterns are expected, are preferred sites of formation of atherosclerosis. Experimental studies have shown that low and oscillating wall shear stress (WSS) plays an important role in the development and progression of atherosclerosis. Accurate estimation of these biomechanical parameters is important to assess the risk of atherosclerosis formation. The coupled effects of non-Newtonian behavior of blood and artery wall flexibility for the transient blood flow through an idealized curved coronary artery are investigated using computational fluid dynamics (CFD) as well as fluid–structure interaction (FSI) simulations. The choice of fluid model, Carreau and Newtonian, was found to impact the time averaged and minimum WSS values. The effects of wall deformation on time averaged wall shear tress were negligible. However, a comparison of temporal minima of WSS along the curvature showed significant variations between CFD and FSI simulations. Since low WSS values are crucial in the prediction of atherosclerosis development, it is concluded that both the non-Newtonian behavior of blood and the wall flexibility should be considered for computational studies.

Fluid structure interaction (FSI) problems are becoming highly complex as FSI has vast applications, which help to model many real life problems. Here, a oneway coupling strategy has been proposed for the FSI problem, where fluid has been modelled in computational fluid dynamics (CFD) and its interface with the solid structure has been modelled with a no-slip no-penetration boundary condition. Using Abaqus CFD simulations, the calculated interface pressure has been applied on the POD modes of the solid structure domain to obtain the displacement field. Here, we assumed that the motion of the flexible solid structure has no effects on the fluid flow as it is a one-way coupling. This assumption is well governed for the less flexible structure. However, it has been noted that this shows good predictions for flexible structures too. The benefit of this approach is that for the same interface boundary of the FSI domain, we can change the structural material properties and predict the results without going for the complete FSI simulation problem. Here, we solved a case study problem example for the fluid flow over a flexible beam and results are validated using the Abaqus FSI Cosimulation.