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.

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.

scholarly journals A Simplified Model for Predicting Friction Factors of Laminar Blood Flow in Small-Caliber Vessels

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 75 ◽  
Author(s):  
Aikaterini Mouza ◽  
Olga Skordia ◽  
Ioannis Tzouganatos ◽  
Spiros Paras
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Friction Factor ◽  
Small Diameter ◽  
Numerical Data ◽  
Blood Flow Rate ◽  
Vessel Diameter ◽  
Simplified Model ◽  
Glycerol Solution ◽  
Fanning Friction Factor

The aim of this study was to provide scientists with a straightforward correlation that can be applied to the prediction of the Fanning friction factor and consequently the pressure drop that arises during blood flow in small-caliber vessels. Due to the small diameter of the conduit, the Reynolds numbers are low and thus the flow is laminar. This study has been conducted using Computational Fluid Dynamics (CFD) simulations validated with relevant experimental data, acquired using an appropriate experimental setup. The experiments relate to the pressure drop measurement during the flow of a blood analogue that follows the Casson model, i.e., an aqueous Glycerol solution that contains a small amount of Xanthan gum and exhibits similar behavior to blood, in a smooth, stainless steel microtube (L = 50 mm and D = 400 μm). The interpretation of the resulting numerical data led to the proposal of a simplified model that incorporates the effect of the blood flow rate, the hematocrit value (35–55%) and the vessel diameter (300–1800 μm) and predicts, with better than ±10% accuracy, the Fanning friction factor and consequently the pressure drop during laminar blood flow in healthy small-caliber vessels.

Steady Laminar Flow through Twisted Pipes: Fluid Flow in Square Tubes

1981 ◽  
Vol 103 (4) ◽  
pp. 785-790 ◽  
Author(s):  
J. H. Masliyah ◽  
K. Nandakumar
Keyword(s):  
Laminar Flow ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Dissipation Term ◽  
Axial Velocity Profile ◽  
Secondary Motion ◽  
Qualitative Nature ◽  
Flow Through ◽  
Steady Laminar

The Navier-Stokes equation in a rotating frame of reference is solved numerically to obtain the flow field for a steady, fully developed laminar flow of a Newtonian fluid in a twisted tube having a square cross-section. The macroscopic force and energy balance equations and the viscous dissipation term are presented in terms of variables in a rotating reference frame. The computed values of friction factor are presented for dimensionless twist ratios, (i.e., length of tube over a rotation of π radians normalized with respect to half the width of tube) of 20, 10, 5 and 2.5 and for Reynolds numbers up to 2000. The qualitative nature of the axial velocity profile was observed to be unaffected by the swirling motion. The secondary motion was found to be most important near the wall.

Converting steady laminar flow to oscillatory flow through a hydroelasticity approach at microscales

Lab on a Chip ◽  
2012 ◽  
Vol 12 (1) ◽  
pp. 60-64 ◽  
Author(s):  
H. M. Xia ◽  
Z. P. Wang ◽  
W. Fan ◽  
A. Wijaya ◽  
W. Wang ◽  
...  
Keyword(s):  
Laminar Flow ◽  
Oscillatory Flow ◽  
Flow Through ◽  
Steady Laminar

scholarly journals Variation of Pressure Drop along the Straight and Bifurcated Channel: Experiment and Simulation

2019 ◽  
Vol 8 (12) ◽  
pp. 2728-2731
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Aspect Ratio ◽  
Computational Model ◽  
Flow Rate ◽  
Normal Water ◽  
Flow Through ◽  
Experiment And Simulation

This paper derives an experimental and simulated investigation carried to analyze the performance of channel for calculating the pressure drop in laminar flow through rectangular shaped (straight and branched) microchannels. The microchannels taken ranged in variable aspect ratio from 0.75 to 1. Every check piece was made from copper and contained only one channel along a direction. The experiments were conducted with normal water, with Reynolds range starting from some 720 to 3500. Predictions obtained supported that with the variation in the aspect ratio the properties of the fluid also change. It is observed that the pressure drop changes with the change in the aspect ratio and flow rate and found that there is a correlation between the experimental and computational model results.

MONITORING OF THE STATE OF THE SKIN BLOOD FLOW IN THE DYNAMICS OF EXPERIMENTAL BURN DISEASE DEVELOPMENT

2020 ◽  
Author(s):  
A. Martusevich ◽  
A Epishkina ◽  
E Golygina ◽  
A Tuzhilkin ◽  
A Fedotova
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Negative Impact ◽  
Small Diameter ◽  
The State ◽  
Disease Development ◽  
Skin Microcirculation ◽  
Experimental Burn ◽  
Flow Through ◽  
Burn Disease

The purpose of this study was to study the state of skin microcirculation in healthy and burned rats. It was found that thermal trauma has a negative impact on the microcirculation system, which is manifested in a decrease in the intensity of blood flow through small-diameter vessels

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