4D flow MRI and CFD simulations of pulsatile flow in a phantom model of arterial stenosis: visualizing the vortex dynamics

We compared steady and pulsatile CFD simulations with 4D Flow MRI in a phantom model of arterial stenosis and investigated the hemodynamic features distal to the occlusion. With CFD, we characterized the flow structure to estimate both the magnitude and degree of anisotropy of the turbulence-related indices including vorticity, wall shear stress, helicity, and swirling strength using Large-Eddy Simulation (LES) and Reynolds-Averaged Navier Stocks (RANS) method. The results revealed that the LES approach captures well both the overall and the detailed ow features in comparison to RANS predictions with the standard k-epsilon model when compared with 4D Flow MRI. Furthermore, the Q-criterion was employed to reveal the temporal evolution of the vortex ring which was observed distal to the stenotic narrowing. It was found that both RANS and LES simulations were highly accurate for wall shear stress when validated against 4D Flow MR Imaging.