The influences of geometry on the hemodynamics and particle transport in model aorta

Abstract

The present study investigates the influences of aorta geometry on hemodynamics and material transport. Based on the observation of the human aorta, two geometric parameters are examined for a model aorta, saying the angle spanned by the main aortic arc and the diameter of the descending aorta. Direct numerical simulations are conducted for nine model aortas with different combinations of aorta arc and outlet diameter. Results reveal that the outlet diameter has a significant impact on aorta hemodynamics. A smaller outlet diameter compared to the inlet leads to accelerated blood flow in the descending segment, affecting flow morphology including the vortex structures, and increasing peak pressure gradient and wall shear stress. However, it reduces the oscillatory shear index, indicating a more organized flow. Analyses show faster particle transport and reduced accumulative residence time for smaller outlet diameters. The arc angle has less significant effects on these properties, except for delaying the time to reach the maximum pressure gradient during ejection. The research results may suggest that the diameter of the aortic outlet has a greater impact on the flow structures, while the arc angle has a relatively less effect. These findings provide insights into the relation between hemodynamics and aorta geometry, with potential clinical implications.