Influence of Turbulence in Aorta-like Tube: Computational and Experimental Study

Publish Year: 1400
نوع سند: مقاله ژورنالی
زبان: English
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شناسه ملی سند علمی:

JR_JAFM-14-5_011

تاریخ نمایه سازی: 8 دی 1400

Abstract:

The presented paper aims at comparison of modelling approaches to a pulsatile fluid flow in aorta-like tube; it investigates their influence on the shape of the velocity profiles and waveforms, and consequently on wall shear stress. Comparisons of computational results between rigid and compliant tubes with laminar and low Re turbulent models of fluid are presented. The results were validated with PIV experimental data through the velocity profile in the half-length section of the tube for both cases (rigid and compliant) and the overall agreement was very good, almost perfect for the rigid case. Frequency of the pulse pump in the experimental circuit was ۱Hz, the diameter of the tube ~ ۲۰ mm, and maximum deformation of the compliant tube during a period was ۱۲%. The turbulent model improved the agreement with the experimental data by flattening the velocity profiles in both cases, but the effect was much more pronounced for the compliant tube, especially during the deceleration phase. This work confirms the hypothesis stated by Brindise and Vlachos (۲۰۱۸) that a longer deceleration phase triggers transition to turbulence. We put foundations for extension of this hypothesis to compliant tubes where this conclusion was confirmed for physiological Reynolds and Womersley numbers. The main outputs of this study are: (i) the length of deceleration phase should be considered (in addition to the geometry or severity of stenosis) in decision whether fluid simulations should be performed with or without laminar flow assumption; (ii) for fluid simulations of blood vessels considering their compliance, a special care should be devoted to time synchronization between BCs to prevent unphysiological waveforms.

Authors

J. Jagos

Faculty of Mechanical Engineering, Brno University of Technology, Brno, ۶۱۶ ۶۹, Czech Republic

J. Kohut

Faculty of Mechanical Engineering, Brno University of Technology, Brno, ۶۱۶ ۶۹, Czech Republic

M. Kotek

Department of Physical Measurement, Technical University of Liberec, Liberec, ۴۶۱ ۱۷, Czech Republic

P. Skacel

Faculty of Mechanical Engineering, Brno University of Technology, Brno, ۶۱۶ ۶۹, Czech Republic

J. Bursa

Faculty of Mechanical Engineering, Brno University of Technology, Brno, ۶۱۶ ۶۹, Czech Republic