Publication detail

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

JAGOŠ, J. KOHÚT, J. KOTEK, M. SKÁCEL, P. BURŠA, J.

English title

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

Type

journal article in Web of Science

Language

en

Original 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 1Hz, the diameter of the tube similar to 20 mm, and maximum deformation of the compliant tube during a period was 12%. 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 (2018) 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.

English 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 1Hz, the diameter of the tube similar to 20 mm, and maximum deformation of the compliant tube during a period was 12%. 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 (2018) 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.

Keywords in English

Pulsatile flow; Pulse wave velocity; Compliant tube; Low Re turbulent model; Boundary condition

Released

01.09.2021

Publisher

Isfahan University of Technology

Location

ISFAHAN

ISSN

1735-3645

Volume

14

Number

5

Pages from–to

1411–1420

Pages count

10

BIBTEX


@article{BUT172470,
  author="Jiří {Jagoš} and Jiří {Kohút} and Michal {Kotek} and Pavel {Skácel} and Jiří {Burša},
  title="Influence of Turbulence in Aorta-like Tube: Computational and Experimental Study",
  year="2021",
  volume="14",
  number="5",
  month="September",
  pages="1411--1420",
  publisher="Isfahan University of Technology",
  address="ISFAHAN",
  issn="1735-3645"
}