Two-equation Turbulence Modeling of Pulsatile Flow in a Stenosed Tube

Ryval, J.; Straatman, Anthony G.; Steinman, David A.

doi:10.1115/1.1798055

Cited by 84 publications

(57 citation statements)

References 19 publications

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“…Some assumed the blood flow in coronary arteries to be laminar (7)(8)(9)(10)(11)(12)(13)(14) and behave as Newtonian fluid (8,(15)(16)(17) and some studied turbulence transition and non-Newtonian effects considering idealized straight arterial model with single model stenosis obstruction (11,15,(17)(18)(19)(20)(21). Several experimental investigations have been carried out on flow disturbances in the downstream region of idealized modeled stenosis (18,22,23).…”

Section: Introductionmentioning

confidence: 99%

“…Transitional shear stress transport (SST) k-ω turbulence model is utilized here to capture the flow transition, if any, to turbulent state. Transitional SST k-ω model has been found to capture turbulence transition and predict WSS better than standard RANS based turbulence models (19,21,26). The onset of turbulent transition during pulsatile flow through coronary arteries is quantitatively analysed by calculating the turbulent kinetic energies at distal locations for varying degree of stenosis.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Mahalingam¹,

Gawandalkar²,

Kini³

et al. 2016

Cardiovasc. Diagn. Ther.

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Background: Local hemodynamics plays an important role in atherogenesis and the progression of coronary atherosclerosis disease (CAD). The primary biological effect due to blood turbulence is the change in wall shear stress (WSS) on the endothelial cell membrane, while the local oscillatory nature of the blood flow affects the physiological changes in the coronary artery. In coronary arteries, the blood flow Reynolds number ranges from few tens to several hundreds and hence it is generally assumed to be laminar while calculating the WSS calculations. However, the pulsatile blood flow through coronary arteries under stenotic condition could result in transition from laminar to turbulent flow condition.Methods: In the present work, the onset of turbulent transition during pulsatile flow through coronary arteries for varying degree of stenosis (i.e., 0%, 30%, 50% and 70%) is quantitatively analyzed by calculating the turbulent parameters distal to the stenosis. Also, the effect of turbulence transition on hemodynamic parameters such as WSS and oscillatory shear index (OSI) for varying degree of stenosis is quantified. The validated transitional shear stress transport (SST) k-ω model used in the present investigation is the best suited Reynolds averaged Navier-Stokes turbulence model to capture the turbulent transition. The arterial wall is assumed to be rigid and the dynamic curvature effect due to myocardial contraction on the blood flow has been neglected.Results: Our observations shows that for stenosis 50% and above, the WSS avg , WSS max and OSI calculated using turbulence model deviates from laminar by more than 10% and the flow disturbances seems to significantly increase only after 70% stenosis. Our model shows reliability and completely validated.Conclusions: Blood flow through stenosed coronary arteries seems to be turbulent in nature for area stenosis above 70% and the transition to turbulent flow begins from 50% stenosis.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Mahalingam¹,

Gawandalkar²,

Kini³

et al. 2016

Cardiovasc. Diagn. Ther.

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“…In the present study, d was chosen to be 0.5 that led to a 75 per cent reduction in the cross-sectional area of the lumen. The artery was extended 4D upstream and 16D downstream of the stenosis, respectively [27]. where u l and p l represent, respectively, the fluid velocity vector and the pressure, r the density of blood (r ¼ 1050 kg m 23 ) and t the stress tensor [28] t ¼ 2hð _ gÞS; ð2:4Þ…”

Section: Geometry Of the Modelmentioning

confidence: 99%

Nitric oxide transport in an axisymmetric stenosis

Liu

Fan

et al. 2012

J. R. Soc. Interface.

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To test the hypothesis that disturbed flow can impede the transport of nitric oxide (NO) in the artery and hence induce atherogenesis, we used a lumen -wall model of an idealized arterial stenosis with NO produced at the blood vessel -wall interface to study the transport of NO in the stenosis. Blood flows in the lumen and through the arterial wall were simulated by Navier -Stokes equations and Darcy's Law, respectively. Meanwhile, the transport of NO in the lumen and the transport of NO within the arterial wall were modelled by advection -diffusion reaction equations. Coupling of fluid dynamics at the endothelium was achieved by the Kedem -Katchalsky equations. The results showed that both the hydraulic conductivity of the endothelium and the non-Newtonian viscous behaviour of blood had little effect on the distribution of NO. However, the blood flow rate, stenosis severity, red blood cells (RBCs), RBC-free layer and NO production rate at the blood vessel -wall interface could significantly affect the transport of NO. The theoretical study revealed that the transport of NO was significantly hindered in the disturbed flow region distal to the stenosis. The reduced NO concentration in the disturbed flow region might play an important role in the localized genesis and development of atherosclerosis.

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“…RANS models (see Sec. 2.2.1) have been explored for turbulent and transitional biofluid problems, but so far with moderate success [49][50][51]. Instead scale resolving simulation (SRS), particularly LES [52,53] (described in Sec.…”

Section: Progress Within Related Research Fieldsmentioning

confidence: 99%

Turbulent Flow in Constricted Blood Vessels : Quantification of Wall Shear Stress Using Large Eddy Simulation

Gårdhagen¹

2013

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No part of this publication may be reproduced, stored in a retrieval system, or be transmitted, in any form or by any means, electronic, mechanic, photocopying, recording, or otherwise, without prior permission of the author.Cover: Pipe flow becomming turbulent after a constriction. Streamlines, wall shear stress on the surface, and vorticity in three cross sections. AbstractThe genesis of atherosclerosis has previously been shown to be affected by the frictional load from the blood on the vessel wall, called the wall shear stress (WSS). Assessment of WSS can therefore provide important information for diagnoses, intervention planning, and follow-up. Calculation of WSS requires highresolved velocity data from the vessel, which in turn can be obtained using computational fluid dynamics (CFD). In this work large eddy simulation LES was successfully used to simulate transitional flow in idealized as well as subject specific vessel models. It was shown that a scale resolving technique is to prefer for this application, since much valuable information otherwise is lost. Besides, Reynolds-Averaged Navier-Stokes (RANS) models have generally failed to predict this type of flow.Non-pulsating flows of Reynolds numbers up to 2 000 in a circular constricted pipe showed that turbulence is likely to occur in the post-stenotic region, which resulted in a complex WSS pattern characterized by large spatial as well temporal fluctuations in all directions along the wall. Time averaged streamwise WSS was relatively high, while time averaged circumferential WSS was low, meaning that endothelial cells in that region would be exposed to oscillations in a stretched state in the streamwise direction and in a relaxed state in the circumferential direction.Since every vessel is unique, so is also its WSS pattern. Hence the CFD simulations must be done in subject specific vessel models. Such can be created from anatomical information acquired with magnetic resonance imaging (MRI). MRI can also be used to obtain velocity boundary conditions for the simulation. This technique was used to investigate pulsating flow in a subject specific normal human aorta. It was shown that even the flow in healthy vessels can be very disturbed and turbulence like, and even for this case large WSS variations were seen. It was also shown that regions around branches from the aorta, known to be susceptible for atherosclerosis, were characterized by high time averaged WSS and high oscillatory shear index.Finally, the predictive capability of CFD was investigated. An idealized model of a human aorta with a coarctation and post-stenotic dilatation was studied before and after a possible repair of the constriction. The results suggested that iii small remaining abnormalities in the geometry may deteriorate the chances for a successful treatment. Also, high values of shear rate and Reynolds stresses were found in the dilatation after the constriction, which previous works have shown means increased risk for thrombus formation and hemolysis. iv Populärvetenskaplig be...

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Two-equation Turbulence Modeling of Pulsatile Flow in a Stenosed Tube

Cited by 84 publications

References 19 publications

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Nitric oxide transport in an axisymmetric stenosis

Turbulent Flow in Constricted Blood Vessels : Quantification of Wall Shear Stress Using Large Eddy Simulation

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