Aortic stenosis is one of the most common valvular heart diseases. In severe cases, the native valve must be replaced by an aortic valve prosthesis which may be either made of technical materials (mechanical valves) or of biological tissue (bioprosthetic valves). Although bioprosthetic valves offer better hemodynamics than mechanical valves, they are nevertheless known to lead to turbulent systolic blood flow which has been connected to blood trauma, leaflet fluttering and adverse events in the ascending aorta due to unphysiological stimulation of the endothelium. Therefore, it is desirable to reduce or even eliminate the production of turbulent systolic flow past bioprosthetic valves.

In this study, we aim at developing a better understanding of the mechanisms leading to turbulent flow past bioprosthetic valves which is a prerequisite for developing strategies to reduce turbulence. To this end, we have devised a computational model for fluid-structure interaction (FSI) in cardiovascular configurations (Nestola et al., 2018). The model comprises a finite-element solver for the full elastodynamics equations of the structure (aortic root, ascending aorta, bioprosthetic valve) and a high-order finite-difference solver for the Navier–Stokes equations for the direct numerical simulation of laminar and turbulent blood flow. The flow solver and the structural solver are coupled with the immersed boundary method where the fluid velocities and the mechanical responses of the structure are transferred between a Cartesian fluid grid and an unstructured finite element mesh by a variational approach.