The implications of two outlet boundary conditions on blood flow simulations in normal aorta of pediatric subjects

The blood flow in a normal aorta is simulated directly based on patient-specific data for boundary conditions. This study provides insight into the implications of using two different outlet boundary conditions in accurate modeling of the blood flow based on using pressure or flow rate outlet boundary conditions. Both boundary conditions at the outlet provided similar blood flow characteristics through the main aortic pathway with a reasonable accuracy of 4% relative to the laboratory measurements. Compared to the pressure outlet boundary condition, however, specifying the flow rate at the outlet underestimates pressure in the aortic arch and the flow rates through the outlets of the aortic arch. Additionally, using the flow rate boundary condition leads to an overestimation of peak local Reynolds Number in the aortic arch, and an inaccurate prediction of transition to turbulence.