Relative residence time and oscillatory shear index of non-Newtonian flow models in aorta

Soulis, Johannes V.; Lampri, Olga P.; Fytanidis, Dimitrios K.; Giannoglou, George D.

doi:10.1109/iwbe.2011.6079011

Cited by 46 publications

(38 citation statements)

References 7 publications

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“…However, this study in general agrees with the findings of Soulis et al (2011b), who suggested that at low shear rates the use of the non-Newtonian power-law model approximates the WSS and the blood viscosity calculations in a more satisfactory way than the simple power-law, Carreau and Casson (Casson 1959;Fung 1993) models. In addition, Bourantas et al (2011) andLiu et al (2011) also found that at high-flow velocities, blood can be treated approximately as a Newtonian fluid with constant viscosity in most regions of the TA under steady flow conditions.…”

Section: Discussionsupporting

confidence: 91%

“…Although the effect of blood viscosity on the flow field within the TA has been studied by some investigators using different non-Newtonian viscosity models (Soulis et al 2009;Renner et al 2009aRenner et al , 2009bBourantas et al 2011;Liu et al 2011;Soulis et al 2011aSoulis et al , 2011b, the current study is, to our knowledge, the first detailed numerical investigation that Computer Methods in Biomechanics and Biomedical Engineering 15 compared various blood viscosity models using a patientspecific geometric model of the TA under steady-state flow conditions. Finally, the study shows that, when studying the WSS distribution for transient blood flow in the TA, the use of a Newtonian blood model might be a reasonably good approximation.…”

Section: Discussionmentioning

confidence: 97%

“…In addition, some preliminary transient results are presented. Although the effect of blood viscosity on flow field within the TA has been studied by some investigators using different nonNewtonian models (Soulis et al 2009;Bourantas et al 2011;Liu et al 2011;Soulis et al 2011aSoulis et al , 2011b, the current study is, to our knowledge, the first detailed numerical investigation that has compared various blood viscosity models using a patient-specific geometric model of the TA under steady-state flow conditions. For a recent comprehensive review on CFD modelling in human TA, we refer to Caballero and Laín (2013).…”

Section: Introductionmentioning

confidence: 97%

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Numerical simulation of non-Newtonian blood flow dynamics in human thoracic aorta

Caballero

Laı́n

2014

Computer Methods in Biomechanics and Biomedical Engineering

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Three non-Newtonian blood viscosity models plus the Newtonian one are analysed for a patient-specific thoracic aorta anatomical model under steady-state flow conditions via wall shear stress (WSS) distribution, non-Newtonian importance factors, blood viscosity and shear rate. All blood viscosity models yield a consistent WSS distribution pattern. The WSS magnitude, however, is influenced by the model used. WSS is found to be the lowest in the vicinity of the three arch branches and along the distal walls of the branches themselves. In this region, the local non-Newtonian importance factor and the blood viscosity are elevated, and the shear rate is low. The present study revealed that the Newtonian assumption is a good approximation at mid-and-high flow velocities, as the greater the blood flow, the higher the shear rate near the arterial wall. Furthermore, the capabilities of the applied non-Newtonian models appeared at low-flow velocities. It is concluded that, while the non-Newtonian power-law model approximates the blood viscosity and WSS calculations in a more satisfactory way than the other non-Newtonian models at low shear rates, a cautious approach is given in the use of this blood viscosity model. Finally, some preliminary transient results are presented.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

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Numerical simulation of non-Newtonian blood flow dynamics in human thoracic aorta

Caballero

Laı́n

2014

Computer Methods in Biomechanics and Biomedical Engineering

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“…OSI is one of the mechanical parameters related to the oscillation of a flow and shows the deviation of the WSS vector from the mainstream blood flow in a cardiac cycle. OSI varies from 0 to 0.5 [20]. The following formulations are used for determining the OSI and mean WSS:…”

Section: Resultsmentioning

confidence: 99%

Numerical simulation of hemodynamic parameters of turbulent and pulsatile blood flow in flexible artery with single and double stenoses

2015

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This article investigates the pulsatile and turbulent blood flows in flexible artery with single and double stenoses. The changes in pressure drop, mean wall shear stress (WSS), radial displacement of the artery, and oscillating shear index are investigated. Similar to experimental data, the results of the present study show that a laminar flow occurs for stenosis of up to 70%, and for 80% stenosis the flow is turbulent. The mean WSS analysis shows that assuming the flow is laminar causes more errors than assuming the walls are solid. The comparison of the results for single stenosis with those for double stenosis reveals that the dilation in the arterial walls in double stenoses is much more common than in single stenosis. Therefore, the maximum mean WSS in double stenoses is less than that in single stenosis. The results also indicate that the axial pressure drop in double stenoses is higher than that in single stenosis.

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“…patient, and the maximum pulsating inflow velocity is taken as 0.35 m/s [11,15,18,22,26,28,30,31,39]. Figure 1d demonstrates the pulse for inlet velocity.…”

Section: Governing Equations and Boundary Conditionsmentioning

confidence: 99%

Effects of severity and location of stenosis on the hemodynamics in human aorta and its branches

Dabagh

Vasava

Jalali

2015

Med Biol Eng Comput

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Pulsatile blood flow is studied in a three-dimensional model of human thoracic aorta at different stages of atherosclerotic lesion growth, taking into account the effect of atherosclerotic plaque location and peripheral symmetry. The model is reconstructed from the computed tomography images. The wall shear stress (WSS), time-averaged WSS, and the oscillatory shear index are applied to determine susceptible sites for the onset of early atherosclerosis. Then, two different degrees of stenosis severity, 50 and 80 %, are introduced to vulnerable areas of the healthy aorta geometry. The overriding issue addressed is that the WSS distribution and magnitude are strongly affected by the atherosclerotic plaque size, its symmetric features, and the location, i.e., the branch it is formed. The present study, for the first time, is capable of providing information on the high shear environment that may exist upon the rupture of plaque surface and any thrombosis due to platelet deposition. The magnitude of WSS and its distribution at the throat of 50 % stenosed aortic arch are in agreement with the previous numerical study (Huang et al. in Exp Fluids 48(3):497-508, 2010). Results show that WSS values exceed 50 Pa at the throat of 80 % stenosed left common carotid and brachiocephalic arteries.

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Relative residence time and oscillatory shear index of non-Newtonian flow models in aorta

Cited by 46 publications

References 7 publications

Numerical simulation of non-Newtonian blood flow dynamics in human thoracic aorta

Numerical simulation of non-Newtonian blood flow dynamics in human thoracic aorta

Numerical simulation of hemodynamic parameters of turbulent and pulsatile blood flow in flexible artery with single and double stenoses

Effects of severity and location of stenosis on the hemodynamics in human aorta and its branches

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