The influence of inlet velocity profile on predicted flow in type B aortic dissection
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ORIGINAL PAPER
The influence of inlet velocity profile on predicted flow in type B aortic dissection Chlöe Harriet Armour1 · Baolei Guo2 · Selene Pirola1 · Simone Saitta1 · Yifan Liu2 · Zhihui Dong2 · Xiao Yun Xu1 Received: 23 June 2020 / Accepted: 6 October 2020 © The Author(s) 2020
Abstract In order for computational fluid dynamics to provide quantitative parameters to aid in the clinical assessment of type B aortic dissection, the results must accurately mimic the hemodynamic environment within the aorta. The choice of inlet velocity profile (IVP) therefore is crucial; however, idealised profiles are often adopted, and the effect of IVP on hemodynamics in a dissected aorta is unclear. This study examined two scenarios with respect to the influence of IVP—using (a) patient-specific data in the form of a three-directional (3D), through-plane (TP) or flat IVP; and (b) non-patient-specific flow waveform. The results obtained from nine simulations using patient-specific data showed that all forms of IVP were able to reproduce global flow patterns as observed with 4D flow magnetic resonance imaging. Differences in maximum velocity and time-averaged wall shear stress near the primary entry tear were up to 3% and 6%, respectively, while pressure differences across the true and false lumen differed by up to 6%. More notable variations were found in regions of low wall shear stress when the primary entry tear was close to the left subclavian artery. The results obtained with non-patient-specific waveforms were markedly different. Throughout the aorta, a 25% reduction in stroke volume resulted in up to 28% and 35% reduction in velocity and wall shear stress, respectively, while the shape of flow waveform had a profound influence on the predicted pressure. The results of this study suggest that 3D, TP and flat IVPs all yield reasonably similar velocity and time-averaged wall shear stress results, but TP IVPs should be used where possible for better prediction of pressure. In the absence of patient-specific velocity data, effort should be made to acquire patient’s stroke volume and adjust the applied IVP accordingly. Keywords Type B aortic dissection · Computation fluid dynamics · Inlet boundary condition · Patient-specific simulation
1 Introduction The choice of inlet boundary condition is crucial to ensure accuracy and validity of numerical solutions in any computational fluid dynamic (CFD) simulation. For CFD analysis of the aorta, it is important to employ a physiological boundary Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10237-020-01395-4) contains supplementary material, which is available to authorized users. * Zhihui Dong dong.zhihui@zs‑hospital.sh.cn * Xiao Yun Xu [email protected] 1
Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK
Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
2
condition that faithfully mimics the ejection of blood from the
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