scholarly journals Numerical Modeling of Blood Flow in Irregular Stenosed Artery with the Effects of Gravity

2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Tan Yan Bin ◽  
Norzieha Mustapha
Keyword(s):  
Blood Flow ◽  
Gravitational Force ◽  
Stokes Equations ◽  
Numerical Study ◽  
Momentum Equation ◽  
Navier Stokes ◽  
Governing Equations ◽  
Navier Stokes Equations ◽  
Stenosed Artery ◽  
Flow Through

A numerical study on the influences of gravitational force on an unsteady two–dimensional nonlinear model of blood flow through a stenosed artery is presented. Blood flow through the constricted region with an irregular stenosis is considered as incompressible Newtonian fluid. The governing equations are derived from the Navier–Stokes equations, which also comprise a significant term for gravitational force in the axial momentum equation. The numerical method chosen in this study is the finite difference approximations based on Marker and Cell (MAC) method at which governing equations are develop in staggered grids for discretization. The Poisson equation of pressure is solved by successive–over–relaxation (S.O.R.) method. Pressure–velocity corrector is imposed to increase accuracy. Streamlines, wall shear stress and axial velocity profiles are plotted.

scholarly journals Numerical simulation of pulsatile blood flow: a study with normal artery, and arteries with single and multiple stenosis

2021 ◽  
Vol 68 (1) ◽  
Author(s):  
Md. Alamgir Kabir ◽  
Md. Ferdous Alam ◽  
Md. Ashraf Uddin
Keyword(s):  
Blood Flow ◽  
Numerical Simulations ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Area Reduction ◽  
Significant Difference ◽  
Stenosed Artery ◽  
Fluid Properties ◽  
Flow Through

AbstractNumerical simulations of pulsatile transitional blood flow through symmetric stenosed arteries with different area reductions were performed to investigate the behavior of the blood. Simulations were carried out through Reynolds averaged Navier-Stokes equations and well-known k-ω model was used to evaluate the numerical simulations to assess the changes in velocity distribution, pressure drop, and wall shear stress in the stenosed artery, artery with single and double stenosis at different area reduction. This study found a significant difference in stated fluid properties among the three types of arteries. The fluid properties showed a peak in an occurrence at the stenosis for both in the artery with single and double stenosis. The magnitudes of stated fluid properties increase with the increase of the area reduction. Findings may enable risk assessment of patients with cardiovascular diseases and can play a significant role to find a solution to such types of diseases.

Simulation of Fluid Flow Through a Granular Bed

2006 ◽  
Author(s):  
Arezou Jafari ◽  
S. Mohammad Mousavi
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Packed Bed ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Wide Range ◽  
Duct Geometry ◽  
Flow Through

Numerical study of flow through random packing of non-overlapping spheres in a cylindrical geometry is investigated. Dimensionless pressure drop has been studied for a fluid through the porous media at moderate Reynolds numbers (based on pore permeability and interstitial fluid velocity), and numerical solution of Navier-Stokes equations in three dimensional porous packed bed illustrated in excellent agreement with those reported by Macdonald [1979] in the range of Reynolds number studied. The results compare to the previous work (Soleymani et al., 2002) show more accurate conclusion because the problem of channeling in a duct geometry. By injection of solute into the system, the dispersivity over a wide range of flow rate has been investigated. It is shown that the lateral fluid dispersion coefficients can be calculated by comparing the concentration profiles of solute obtained by numerical simulations and those derived analytically by solving the macroscopic dispersion equation for the present geometry.

scholarly journals Unsteady hybrid nanoparticle-mediated magneto-hemodynamics and heat transfer through an overlapped stenotic artery: Biomedical drug delivery simulation

2021 ◽  
pp. 095441192110260
Author(s):  
Jayati Tripathi ◽  
Buddakkagari Vasu ◽  
Osman Anwar Bég ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Drug Delivery ◽  
Blood Flow ◽  
Stokes Equations ◽  
Volume Fraction ◽  
Hybrid Nanoparticles ◽  
Navier Stokes ◽  
Hybrid Nanofluid ◽  
Two Dimensional ◽  
Governing Equations ◽  
Navier Stokes Equations

Two-dimensional laminar hemodynamics through a diseased artery featuring an overlapped stenosis was simulated theoretically and computationally. This study presented a mathematical model for the unsteady blood flow with hybrid biocompatible nanoparticles (Silver and Gold) inspired by drug delivery applications. A modified Tiwari-Das volume fraction model was adopted for nanoscale effects. Motivated by the magneto-hemodynamics effects, a uniform magnetic field was applied in the radial direction to the blood flow. For realistic blood behavior, Reynolds’ viscosity model was applied in the formulation to represent the temperature dependency of blood. Fourier’s heat conduction law was assumed and heat generation effects were included. Therefore, the governing equations were an extension of the Navier–Stokes equations with magneto-hydrodynamic body force included. The two-dimensional governing equations were transformed and normalized with appropriate variables, and the mild stenotic approximation was implemented. The strongly nonlinear nature of the resulting dimensionless boundary value problem required a robust numerical method, and therefore the FTCS algorithm was deployed. Validation of solutions for the particular case of constant viscosity and non-magnetic blood flow was included. Using clinically realistic hemodynamic data, comprehensive solutions were presented for silver, and silver-gold hybrid mediated blood flow. A comparison between silver and hybrid nanofluid was also included, emphasizing the use of hybrid nanoparticles for minimizing the hemodynamics. Enhancement in magnetic parameter decelerated the axial blood flow in stenotic region. Colored streamline plots for blood, silver nano-doped blood, and hybrid nano-doped blood were also presented. The simulations were relevant to the diffusion of nano-drugs in magnetic targeted treatment of stenosed arterial diseases.

Numerical Study of the Pulsating Flow at the Tongue Region of a Centrifugal Pump for Several Flow Rates

2008 ◽  
Author(s):  
Rau´l Barrio ◽  
Jorge Parrondo ◽  
Eduardo Blanco ◽  
Joaqui´n Ferna´ndez
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Numerical Predictions ◽  
Partial Load ◽  
Flow Through

A numerical study is presented on the unsteady flow at the tongue region of a single suction volute-type centrifugal pump with a specific speed of 0.46. The flow through the pump, available at laboratory, was simulated by means of a commercial CFD software that solved the Reynolds averaged Navier-Stokes equations for three-dimensional unsteady flow (3D-URANS). A sensitivity analysis of the numerical model was carried out and the numerical predictions were compared with previous experimental results of both global and unsteady variables. Once validated, the model was used to study the flow pulsations associated to the interaction between the impeller blades and the volute tongue as a function of the flow rate, from partial load to overload. The study allowed relating the passage of the impeller blades with the tangential and radial velocity pulsations at some reference positions and with the pressure pulsations at the tongue region.

Analysis of Blood flow Through Artery with Mild Stenosis

2020 ◽  
Vol 25 (2) ◽  
pp. 33-38
Author(s):  
Puskar R. Pokhrel ◽  
Jeevan Kafle ◽  
Parameshwari Kattel ◽  
Hari Prasad Gaire
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Stokes Equations ◽  
Arterial Stenosis ◽  
Navier Stokes ◽  
Shear Stresses ◽  
Navier Stokes Equations ◽  
Other Substances ◽  
Blood Flow Dynamics ◽  
Flow Through

Arterial stenosis is an abnormal condition in arteries due to the deposition of fats and other substances, called atherosclerosis.  As it restricts the blood flow, it may induce a heart attack. Employing the Navier-Stokes equations, we consider the blood flow in an artery with the presence of a stenosis in an axisymmetric shape. We analyze the blood flow dynamics in cylindrical form by evaluating pressure, pressure drop against the wall, shear stress on the wall. We also analyze the dynamics by evaluating the ratio of pressure drop with stenosis to the pressure drop without stenosis against the wall, and the ratio of maximum to minimum shear stresses with the ratios of various thicknesses of stenosis to radius of the artery.

scholarly journals Numerical Study of the Blood Flow in a Deformable Human Aorta

2019 ◽  
Vol 9 (6) ◽  
pp. 1216 ◽  
Author(s):  
Marwa Selmi ◽  
Hafedh Belmabrouk ◽  
Abdullah Bajahzar
Keyword(s):  
Blood Flow ◽  
Cardiac Muscle ◽  
Stokes Equations ◽  
Vascular System ◽  
Numerical Study ◽  
Navier Stokes ◽  
Human Aorta ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
Internal Surfaces

In this work, we present a numerical investigation of blood flow in a portion of the human vascular system. More precisely, the present work analyzed the blood flow in the upper portion of the aorta. The aorta and its ramified blood vessels are surrounded by the cardiac muscle. The blood flow generates pressure on the internal surfaces of the artery and its ramifications, thereby causing deformation of the cardiac muscle. The numerical analysis used the Navier–Stokes equations as the governing equations of blood flow for the calculation of the velocity field and pressure distribution in the blood. The neo-Hookean hyperelastic model was used for the description of the behavior of the vessel walls. The velocity and pressure distributions were analyzed. The deformation of the vessel was also investigated. The numerical results could be used to better understand and predict the factors that trigger cardiovascular diseases and distortions of the aorta and as a diagnostic tool in clinical applications.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

scholarly journals Transient Pressure-Driven Electroosmotic Flow through Elliptic Cross-Sectional Microchannels with Various Eccentricities

Computation ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 27
Author(s):  
Nattakarn Numpanviwat ◽  
Pearanat Chuchard
Keyword(s):  
Laplace Transform ◽  
Electroosmotic Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Mathieu Functions ◽  
Navier Stokes Equations ◽  
Flow Rates ◽  
Elliptic Cross ◽  
Flow Through ◽  
Relative Errors

The semi-analytical solution for transient electroosmotic flow through elliptic cylindrical microchannels is derived from the Navier-Stokes equations using the Laplace transform. The electroosmotic force expressed by the linearized Poisson-Boltzmann equation is considered the external force in the Navier-Stokes equations. The velocity field solution is obtained in the form of the Mathieu and modified Mathieu functions and it is capable of describing the flow behavior in the system when the boundary condition is either constant or varied. The fluid velocity is calculated numerically using the inverse Laplace transform in order to describe the transient behavior. Moreover, the flow rates and the relative errors on the flow rates are presented to investigate the effect of eccentricity of the elliptic cross-section. The investigation shows that, when the area of the channel cross-sections is fixed, the relative errors are less than 1% if the eccentricity is not greater than 0.5. As a result, an elliptic channel with the eccentricity not greater than 0.5 can be assumed to be circular when the solution is written in the form of trigonometric functions in order to avoid the difficulty in computing the Mathieu and modified Mathieu functions.

A numerical study of the interaction between unsteay free-stream disturbances and localized variations in surface geometry

1989 ◽  
Vol 209 ◽  
pp. 285-308 ◽  
Author(s):  
R. J. Bodonyi ◽  
W. J. C. Welch ◽  
P. W. Duck ◽  
M. Tadjfar
Keyword(s):  
Numerical Solutions ◽  
Free Stream ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Surface Geometry ◽  
Navier Stokes Equations ◽  
S Waves ◽  
Tollmien Schlichting

A numerical study of the generation of Tollmien-Schlichting (T–S) waves due to the interaction between a small free-stream disturbance and a small localized variation of the surface geometry has been carried out using both finite–difference and spectral methods. The nonlinear steady flow is of the viscous–inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier–Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of the T–S waves generated by the interaction between the free-stream disturbance and the surface distortion, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T–S waves.

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