Influence of streaming potential on pulsatile pressure-gradient driven flow through an annulus

2013 ◽  
Vol 34 (5) ◽  
pp. 691-699 ◽  
Author(s):  
Anish Shenoy ◽  
Jeevanjyoti Chakraborty ◽  
Suman Chakraborty
Keyword(s):  
Pressure Gradient ◽  
Streaming Potential ◽  
Pulsatile Pressure ◽  
Flow Through ◽  
Pulsatile Pressure Gradient

scholarly journals Study of Magnetohydrodynamic Pulsatile Blood Flow through an Inclined Porous Cylindrical Tube with Generalized Time-Nonlocal Shear Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Nehad Ali Shah ◽  
A. Al-Zubaidi ◽  
S. Saleem
Keyword(s):  
Blood Flow ◽  
Pressure Gradient ◽  
Cylindrical Tube ◽  
Transverse Magnetic ◽  
Inverse Laplace Transform ◽  
Pulsatile Pressure ◽  
Significant Difference ◽  
Flow Through ◽  
Mathcad Software ◽  
Pulsatile Pressure Gradient

The effects of pulsatile pressure gradient in the presence of a transverse magnetic field on unsteady blood flow through an inclined tapered cylindrical tube of porous medium are discussed in this article. The fractional calculus technique is used to provide a mathematical model of blood flow with fractional derivatives. The solution of the governing equations is found using integral transformations (Laplace and finite Hankel transforms). For the semianalytical solution, the inverse Laplace transform is found by means of Stehfest’s and Tzou’s algorithms. The numerical calculations were performed by using Mathcad software. The flow is significantly affected by Hartmann number, inclination angle, fractional parameter, permeability parameter, and pulsatile pressure gradient frequency, according to the findings. It is deduced that there exists a significant difference in the velocity of the flow at higher time when the magnitude of Reynolds number is small and large.

scholarly journals Pulsating Flow of an Ostwald—De Waele Fluid between Parallel Plates

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 932
Author(s):  
Rodrigo González ◽  
Aldo Tamburrino ◽  
Andrea Vacca ◽  
Michele Iervolino
Keyword(s):  
Shear Stress ◽  
Analytical Solution ◽  
Wall Shear Stress ◽  
Pressure Gradient ◽  
Velocity Distribution ◽  
Momentum Equation ◽  
Parallel Plates ◽  
Analytical Computation ◽  
Pulsatile Pressure ◽  
Pulsatile Pressure Gradient

The flow between two parallel plates driven by a pulsatile pressure gradient was studied analytically with a second-order velocity expansion. The resulting velocity distribution was compared with a numerical solution of the momentum equation to validate the analytical solution, with excellent agreement between the two approaches. From the velocity distribution, the analytical computation of the discharge, wall shear stress, discharge, and dispersion enhancements were also computed. The influence on the solution of the dimensionless governing parameters and of the value of the rheological index was discussed.

scholarly journals Finite Element Solutions for Non-Newtonian Pulsatile Flow in a Non-Darcian Porous Medium Conduit

2007 ◽  
Vol 12 (3) ◽  
pp. 317-327 ◽  
Author(s):  
R. Bhargava ◽  
H. S. Takhar ◽  
S. Rawat ◽  
Tasveer A. Bég ◽  
O. Anwar Bég
Keyword(s):  
Finite Element ◽  
Pressure Gradient ◽  
Numerical Technique ◽  
Darcy Number ◽  
Gradient Term ◽  
Newtonian Flow ◽  
Polymeric Fluids ◽  
Forchheimer Number ◽  
Pulsatile Pressure ◽  
Flow Through

The present analysis is motivated by the need to elucidate with more accuracy and sophistication the hydrodynamics of non-Newtonian flow via a channel containing a porous material under pulsating pressure gradient. A one-dimensional transient rheological model for pulsating flow through a Darcy-Forcheimmer porous channel is used. A modified Casson non-Newtonian constitutive model is employed for the transport fluid with a drag force formulation for the porous body force effects. The model is transformed and solved using a finite element numerical technique. Rheological effects are examined using a β parameter which vanishes in the limit (Newtonian flow). Velocity profiles are plotted for studying the influence of Reynolds number, Darcy number, Forchheimer number and the β (non-Newtonian) parameter. The channel considered is rigid with a pulsatile pressure applied via an appropriate pressure gradient term. The model finds applications in industrial filtration systems, pumping of polymeric fluids etc.

NUMERICAL SIMULATION OF UNSTEADY TWO-LAYERED PULSATILE BLOOD FLOW IN A STENOSED FLEXIBLE ARTERY: EFFECT OF PERIPHERAL LAYER VISCOSITY

2005 ◽  
Vol 9 (2) ◽  
pp. 99-114 ◽  
Author(s):  
S. Chakravarty ◽  
P. K. Mandal ◽  
A. Mandal
Keyword(s):  
Blood Flow ◽  
Unsteady Flow ◽  
Pressure Gradient ◽  
Cylindrical Tube ◽  
Shear Stresses ◽  
Flow Mechanism ◽  
Moving Wall ◽  
Pulsatile Pressure ◽  
Pulsatile Pressure Gradient ◽  
Good Agreement

The present paper deals with a theoretical investigation of blood flow in an arterial segment in the presence of stenosis. The streaming blood is treated to be composed of two different layers ‐ the central core and the plasma. The former is considered to be non‐Newtonian liquid characterised by the Power law model, while the latter is chosen to be Newtonian. The artery is simulated as an elastic (moving wall) cylindrical tube. The unsteady flow mechanism of the present study is subjected to a pulsatile pressure gradient arising from the normal functioning of the heart. The time‐variant geometry of the stenosis has been accounted for in order to improve resemblance to the real situation. The unsteady flow mechanism, subjected to pulsatile pressure gradient, has been solved using finite difference scheme by exploiting the physically realistic prescribed conditions. An extensive quantitative analysis has been performed through numerical computations of the flow velocity, the flux, the resistive impedances and the wall shear stresses, together with their dependence with the time, the input pressure gradient and the severity of the stenosis, presented graphically at the end of the paper in order to illustrate the applicability of the model under consideration. Special emphasis has been made to compare the existing results with the present ones and found to have a good agreement. Straipsnyje nagrinejamas kraujo srauto tekejimas esant stenozei. Nagrinejamas dvisluoks‐nis kraujo tekejimas. Arterija modeliuojama kaip vamzdis su elastinemis sienelemis. Kraujo srauto nestacionaruma sukelia širdies veikla. Skaitinis sprendinys randamas baigtiniu skirtumu metodu. Atlikta kokybine skaitiniu sprendiniu analize iliustruojanti greičiu, srautu, sieneles itampu priklausomybe laike. Skaitiniai rezultatai pakankamai gerai patvirtina eksperimentinius duomenis.

Hemodynamic Method to Predict Whether Hunterian Ligation of the Basilar Artery Will Lead to Thrombosis of Basilar Bifurcation Aneurysms

Neurosurgery ◽  
1987 ◽  
Vol 20 (2) ◽  
pp. 249-253 ◽  
Author(s):  
Jack Chang ◽  
Margot R. Roach
Keyword(s):  
Pressure Gradient ◽  
Basilar Artery ◽  
Diameter Ratio ◽  
Phase Lag ◽  
Maximal Width ◽  
Before And After ◽  
Simple Measurement ◽  
Flow Through ◽  
Stop Flow

Abstract In some cases, basilar artery aneurysms cannot be repaired surgically and the basilar artery is occluded near the neck of the aneurysm to stop flow into the aneurysm. After the operation, the aneurysm can fill only by flow through the posterior communicating arteries (PCoAs). Hemodynamically, if the flow were the same in both PCoAs and there were no phase lag in the pressures, there would be no pressure gradient for flow to go across the neck of the aneurysm and therefore the aneurysm would thrombose. We have assumed that the diameter of the artery is roughly proportional to the flow that goes through it chronically. We measured the diameters of the PCoAs in 25 patients who had hunterian ligation of the basilar artery. We also measured the maximal width, height, and depth of the aneurysms on angiograms obtained before and after operation. Eleven aneurysms thrombosed completely and had a diameter ratio of > 0.6; 10 aneurysms thrombosed partially and had a diameter ratio of 0.46 ˜ 1.0; 4 aneurysms did not change and had a diameter ratio of <0.45. The ratio of the sizes of the PCoAs pre- and postoperatively was comparable in most cases, so we believe that it is possible to predict reasonably accurately from this simple measurement whether the aneurysm is likely to thrombose if the basilar artery is ligated.

A Topological Study of the Genesis of a Horseshoe Vortex in the Symmetry Plane Due to an Adverse Pressure Gradient

2001 ◽  
Author(s):  
Martijn A. van den Berg ◽  
Michael M. J. Proot ◽  
Peter G. Bakker
Keyword(s):  
Pressure Gradient ◽  
Bifurcation Theory ◽  
Nonlinear Differential Equations ◽  
Nonlinear Dynamical System ◽  
Symmetry Plane ◽  
Adverse Pressure Gradient ◽  
Horseshoe Vortex ◽  
Nonlinear Dynamical ◽  
Separating Flow ◽  
Flow Through

Abstract The present paper describes the genesis of a horseshoe vortex in the symmetry plane in front of a juncture. In contrast to a previous topological investigation, the presence of the obstacle is no longer physically modelled. Instead, the pressure gradient, induced by the obstacle, has been used to represent its influence. Consequently, the results of this investigation can be applied to any symmetrical flow above a flat plate. The genesis of the vortical structure is analysed by using the theory of nonlinear differential equations and the bifurcation theory. In particular, the genesis of a horseshoe vortex can be described by the unfolding of the degenerate singularity resulting from a Jordan Normal Form with three vanishing eigenvalues and one linear term which is related to the adverse pressure gradient. The examination of this nonlinear dynamical system reveals that a horseshoe vortex emanates from a non-separating flow through two subsequent saddle-node bifurcations in different directions and the transition of a node into a focus located in the flow field.

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