scholarly journals Numerical Study of Turbulent Pulsatile Blood Flow through Stenosed Artery Using Fluid-Solid Interaction

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mehdi Jahangiri ◽  
Mohsen Saghafian ◽  
Mahmood Reza Sadeghi
Keyword(s):  
Blood Flow ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Numerical Study ◽  
Reverse Flow ◽  
Flow Region ◽  
Rigid Wall ◽  
Pulsatile Blood Flow ◽  
Artery Wall ◽  
Flow Through

The turbulent pulsatile blood flow through stenosed arteries considering the elastic property of the wall is investigated numerically. During the numerical model validation both standardk-εmodel and RNGK-εmodel are used. Compared with the RNGK-εmodel, the standardK-εmodel shows better agreement with previous experimental results and is better able to show the reverse flow region. Also, compared with experimental data, the results show that, up to 70% stenosis, the flow is laminar and for 80% stenosis the flow becomes turbulent. Assuming laminar or turbulent flow and also rigid or elastic walls, the results are compared with each other. The investigation of time-averaged shear stress and the oscillatory shear index for 80% stenosis show that assuming laminar flow will cause more error than assuming a rigid wall. The results also show that, in turbulent flow compared with laminar flow, the importance of assuming a flexible artery wall is more than assuming a rigid artery wall.

Steady laminar flow of blood through successive restrictions in circular conduits of small diameter

2008 ◽  
Vol 222 (8) ◽  
pp. 1557-1573 ◽  
Author(s):  
D Nag ◽  
A Datta
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Small Diameter ◽  
Rigid Wall ◽  
Pressure Loss Coefficient ◽  
Axial Velocity Distribution ◽  
Recirculation Zones ◽  
Flow Through ◽  
Steady Laminar

In this paper, numerical results on steady laminar flow of blood through an artery having two successive identical axisymmetric restrictions are presented, at varying degrees of restrictions. Physically, such a flow has features in common with steady blood flow through an artery with multiple stenoses. Additionally, results are presented for the blood flow through an artery in the presence of a single restriction, for comparison. The artery has been modelled as a tube with a rigid wall. The rheological characteristics of blood have been assumed both as Newtonian and non-Newtonian. Three different non-Newtonian models of blood — power law, Quemada, and Carreau—Yasuda models — have been considered in the analysis. The haemodynamic effects of the restrictions on the axial velocity distribution, recirculation zones formed downstream to the restrictions, the wall shear stress, and the pressure drop in the artery have been analysed. The irreversible pressure loss coefficient is calculated from the pressure drop and its variation with the degree of stenosis is obtained.

Haemodynamic analysis of coronary artery bypass grafting in a non-linear deformable artery and Newtonian pulsatile blood flow

2008 ◽  
Vol 222 (8) ◽  
pp. 1273-1287 ◽  
Author(s):  
E Kouhi ◽  
Y S Morsi ◽  
S H Masood
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Coronary Artery Bypass Grafting ◽  
Recirculation Zone ◽  
Artery Bypass ◽  
Rigid Wall ◽  
Bypass Grafting ◽  
Pulsatile Blood Flow ◽  
Artery Wall ◽  
Wall Model

A three-dimensional (3D) computational model of stenotic coronary artery bypass grafting (CABG) system with fluid—structure interaction (FSI) using realistic physiological conditions is introduced. Unsteady pulsatile blood flow is applied to the wall of non-linear deformable arteries over the systolic period. In the analysis, the arbitrarily Lagrangian—Eulerian (ALE) formulation is used to couple the fluid region and solid domain. The method couples the equations of the deformation of the artery wall and applies them as the fluid domain boundary condition. The flow distribution and haemodynamic forces are presented in terms of velocity profiles and temporal and spatial wall shear stresses (WSSs) at the distal area. Rapid changes in the flow fields are observed in the early stages of the cardiac cycle, which alters the location of the recirculation zone from the toe to the host bed and then to the heel. The migration of the recirculation zone, considering the effect of deformability of the artery wall, indicates the same trend as the rigid wall model according to the location of low and high WSSs. However, the WSSs in the critical areas such as toe, heel, and suture lines are found to have dramatic drops in magnitudes in comparison with those of the rigid wall model. This could initiate the promotion of intimal hyperplasia (IH) and may cause an early graft failure in CABG.

Influence of Distal Stenosis on Blood Flow Through Coronary Serial Stenoses: A Numerical Study

2019 ◽  
Vol 16 (03) ◽  
pp. 1842003 ◽  
Author(s):  
Biyue Liu ◽  
Dalin Tang
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Numerical Study ◽  
Reverse Flow ◽  
Arterial Segment ◽  
Disturbed Flow ◽  
Curved Artery ◽  
Artery Segment ◽  
Flow Through ◽  
Drop Flow

Computer simulations of the blood flow through right coronary arteries with two stenoses in the same arterial segment are carried out to investigate the interactions of serial stenoses, especially the effect of the distal stenosis. Various mathematical models are developed by varying the location of the distal stenosis. The numerical results show that the variation of the distal stenosis has significant impact on coronary hemodynamics, such as the pressure drop, flow shifting, wall shear stress and flow separation. Our simulations demonstrate that the distal stenosis has insignificant effect on the disturbed flow pattern in the regions of upstream and across the proximal stenosis. In a curved artery segment with two moderate stenoses of the same size, the distal stenosis causes a larger pressure drop and a more disturbed flow field in the poststenotic region than the proximal stenosis does. A distal stenosis located at a further downstream position causes a larger pressure drop and a stronger reverse flow.

scholarly journals Numerical Study of Blood Flow Through Artificial Heart Valves

2021 ◽  
Vol 1094 (1) ◽  
pp. 012120
Author(s):  
Hussein Togun ◽  
Ali Abdul Hussain ◽  
Saja Ahmed ◽  
Iman Abdul hussain ◽  
Huda Shaker
Keyword(s):  
Blood Flow ◽  
Artificial Heart ◽  
Heart Valves ◽  
Numerical Study ◽  
Artificial Heart Valves ◽  
Flow Through

scholarly journals A Simple Transient Poiseuille-Based Approach to Mimic the Womersley Function and to Model Pulsatile Blood Flow

Dynamics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 9-17
Author(s):  
Andrea Natale Impiombato ◽  
Giorgio La Civita ◽  
Francesco Orlandi ◽  
Flavia Schwarz Franceschini Zinani ◽  
Luiz Alberto Oliveira Rocha ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Boundary Conditions ◽  
Quadratic Function ◽  
Pulsatile Blood Flow ◽  
Flow Through ◽  
Simplified Analysis ◽  
Function Models ◽  
Flow Reversals

As it is known, the Womersley function models velocity as a function of radius and time. It has been widely used to simulate the pulsatile blood flow through circular ducts. In this context, the present study is focused on the introduction of a simple function as an approximation of the Womersley function in order to evaluate its accuracy. This approximation consists of a simple quadratic function, suitable to be implemented in most commercial and non-commercial computational fluid dynamics codes, without the aid of external mathematical libraries. The Womersley function and the new function have been implemented here as boundary conditions in OpenFOAM ESI software (v.1906). The discrepancy between the obtained results proved to be within 0.7%, which fully validates the calculation approach implemented here. This approach is valid when a simplified analysis of the system is pointed out, in which flow reversals are not contemplated.

scholarly journals Characteristics of Pulsatile Blood Flow Through 3-D Geometry of Arterial Stenosis

2015 ◽  
Vol 105 ◽  
pp. 877-884 ◽  
Author(s):  
Khairuzzaman Mamun ◽  
Most. Nasrin Akhter ◽  
Md. Shirazul Hoque Mollah ◽  
Md. Abu Naim Sheikh ◽  
Mohammad Ali
Keyword(s):  
Blood Flow ◽  
Arterial Stenosis ◽  
Pulsatile Blood Flow ◽  
Flow Through

scholarly journals Effect of exercise on blood flow through the aortic valve: a combined clinical and numerical study

2013 ◽  
Vol 17 (16) ◽  
pp. 1821-1834 ◽  
Author(s):  
Hamidreza Ghasemi Bahraseman ◽  
Kamran Hassani ◽  
Mahdi Navidbakhsh ◽  
Daniel M. Espino ◽  
Zahra Alizadeh Sani ◽  
...  
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Numerical Study ◽  
Flow Through
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