Search

This article is designed to inspect the thermal effects of an unsteady compressible flow of a viscous fluid through a symmetric channel. Combined effects of convective heat transfer, magnetic field, and radiation are also given special attention in this article. Basic laws of mass, momentum, and energy for compressible flow are employed in the modeling of the current problem. In addition, slip boundary conditions are also implemented in the analysis of the above thermal flow problem. Coupled nonlinear differential equations are solved numerically using explicit finite difference technique. Finally, the influence of different sundry parameters on the axial velocity, flow rate, and heat transfer are visualized through graphs. Time variant behavior of flow rate is calculated. Outcomes of the results reveal that the increment of the flow rate is related to the increase of compressibility parameters. Enhancement in the temperature profiles in the presence of radiation number is also reported. This model is the most general version of peristalsis of compressible flow in view of natural convection and radiation impact with extensive applications in aircraft industry, geophysics, and other industrial situations (cooling of electronic equipment, heat exchangers, and so forth). Key words: magneto-hydrodynamics, natural convection, compressible flow, radiation, Mach number, 1. Introduction Peristalsis is the mechanism in which traveling waves are responsible for fluid flow. It is the natural process that causes the motion of a fluid in human. One [...]

The purpose of this article is to theoretically discuss the unsteady hemo-dynamics of blood through a catheterized overlapping stenotic vessel with nanoparticles. The nature of the blood is characterized by the constitutive Cross model equation. This study is conducted under the assumption of mild stenotic conditions and the equations of momentum and temperature are simplified after making this assumption. Explicit finite difference method is employed to obtain the numerical results of the governing equations. Results for different values of emerging parameters, such as Weissenberg number, Lewis number, thermophoresis parameter, and Brownian motion parameter are shown at different locations of an arterial cross section. These results demonstrate a pictorial way to comprehend the theoretical biomedical problem. These results reveal that Lewis number (Le) and visco-elastic parameter Weissenberg number (We) both are decreasing functions of velocity profiles at each arterial cross section. Furthermore, it is also noted that the thermophoresis parameter ([N.sub.t]) quantitatively decreases the flow of blood inside the vessel while the Brownian motion parameter ([N.sub.b]) shows the opposite effects on blood flow; it increases the magnitude of velocity. Key words: unsteady blood flow, Cross non-Newtonian fluid, nanoparticle, explicit finite difference, Brownian motion, Lewis number. Notre but est une discussion theorique de l'hemodynamique instable du sang a travers un catheter insere dans un vaisseau stenose, en presence de nanoparticules. Nous utilisons le modele constitutif de Cross pour decrire le sang. L'etude se fait sous l'hypothese d'une faible stenose et les equations pour l'impulsion et la temperature sont simplifiees en consequence. Une methode explicite aux differences finies permet de resoudre numeriquement les equations directrices. Les resultats pour differents parametres pertinents, tels le nombre de Weissenberg, le nombre de Lewis, le parametre de thermophorese et le parametre de mouvement brownien, sont presentes a differents points de la section arterielle. Ces resultats nous donnent une approche graphique pour comprendre le probleme biomedical. Ils indiquent que le nombre de Lewis (Le) et le parametre viscoelastique de Weissenberg (We) sont des fonctions decroissantes du profil de vitesse en tout point de la section. De plus, il faut noter que le parametre de thermophorese ([N.sub.t]) est associe a une diminution quantitative du flot sanguin, alors que le parametre de mouvement brownien ([N.sub.b]) est indicatif de l'effet oppose, correspondant a une augmentation de la vitesse. [Traduit par la Redaction] Mots-cles: sang instable, fluide non newtonien de Cross, nanoparticules, methode aux differences finies explicites, movement brownien, nombre de Lewis., 1. Introduction Stenosis, or atherosclerosis, is an arterial disease that changes blood flow patterns significantly. This is quite a common diseases in coronary arteries and is caused by the accumulation [...]

A study is conducted to analyze two-phase flow model of blood in a flexible stenotic artery. The Newtonian and Herschel-Bulkley constitutive relations are used to model the core and peripheral regions, respectively. The arterial wall is assumed to be elastic. By making appropriate assumptions, the flow problem is transformed into a set of nonlinear partial different equations. These equation together with suitable initial and boundary data are solved using an explicit finite difference scheme. The radial and axial velocities of the streaming blood are computed for several values of the emerging parameters. The axial distribution of flow rate, resistance impedance, and wall shear stress are also shown graphically and discussed in detail. The instantaneous streamlines patterns of the flow are also shown. Key words: blood, unsteady pulsatile flow, Herschel-Bulkley, wall deformability, finite difference method. Resume: Nous conduisons une etude du modele d'ecoulement a deux phases pour du sang dans une artere souple stenosee. Les relations constitutives de Newton et de Herschel-Bukley sont utilisees pour modeliser respectivement le creur et les parties peripheriques de l'ecoulement. Les murs de l'artere sont presumes elastiques. En faisant quelques suppositions appropriees, le probleme de l'ecoulement est transforme en un ensemble d'equations differentielles partielles non lineaires. Ces equations, avec des conditions initiales et de limites raisonnables sont solutionnees par une approche aux differences finies. Nous calculons les vitesses axiales et radiales de l'ecoulement sanguin pour differentes valeurs des parametres emergents. Nous discutons en detail le taux d'ecoulement axial, l'impedance de resistance et la contrainte de dechirement au mur. Nous illustrons egalement le patron des lignes d'ecoulement sanguin. [Traduit par la Redaction] Mots-cles: sang, ecoulement pulse instable, Herschel-Buckley, deformabilite du mur, methode aux differences finies., 1. Introduction The study of dynamics of blood flow through arteries with localized narrowing is important because of its relevance in diagnosis and treatment of cardiovascular disease that may lead [...]

This article communicates peristalsis of Jeffrey material in curved geometry. Here, material has temperature-dependent thermal conductivity and viscosity. Mathematical modeling of an inclined magnetic field in curved configuration has been presented in this article. Irreversibility effects have been analyzed through entropy generation. Slip conditions are entertained both for velocity and thermal fields. Problem is first reduced in wave frame and then lubrication approach has been utilized. Numerical solution of dimensionless problem is obtained and important parameters of curiosity are examined. It is noticed that velocity enhances for higher viscosity whereas temperature decreases for higher thermal conductivity coefficient. Velocity of the flow is maximum for inclination of magnetic field to be zero and it is minimum for ϑ o = 90 ∘. Heat transfer parameter enhances both for thermal conductivity parameter and Hartmann number. Temperature is high for curved configuration when compared with straight channel. It is observed that entropy remains unchanged in center of the channel and it is maximum near the channel walls. Entropy generation decays near the channel walls by higher viscosity and thermal conductivity parameters. However, entropy is more for higher inclination of magnetic field. [ABSTRACT FROM AUTHOR]

The creeping flow of a tangent hyperbolic liquid via a channel of porous walls is discussed in this article. For the formulation of problem, the laws of conservation of mass, momentum, and energy are used. A description of fluid leakage through channel walls is provided by Darcy's law. An analytical solution to the equations of motion is determined with appropriate physical approximations by applying the perturbation technique. Expressions for the hydrostatic pressure, velocity field, and temperature are found. The flow characteristics of tangent hyperbolic fluid are affected by the filtration coefficient and inlet pressure, which are also discussed. Graphs are used to discuss the effects of the inlet pressure, the Wiessenberg number, the magnetic field, the law index, the Brickman number, and the wall filtration parameter on the flow characteristics. The mean pressure difference is shown to be increased by the magnetic field. The derived data are used in a flat plate hemodialyzer to investigate the filtrate flow. The theoretical values for the hemodialyzer's mean pressure difference and filtration rate are computed using the derived solutions. A reasonable agreement is established between the calculated results and the experimental data. It is determined that the fluid flow in a flat plate hemodialyzer can be studied hydrodynamically using the model that is presented. A flat plate hemodialyzer's filtrate flow is examined by using the results that were obtained. [ABSTRACT FROM AUTHOR]

A theoretical study of an unsteady two-layered blood flow through a stenosed artery is presented in this article. The geometry of a rigid stenosed artery is assumed to be $w$-shaped. The flow regime is assumed to be laminar, unsteady and uni-directional. The characteristics of blood are modelled by the generalized Oldroyd-B non-Newtonian fluid model in the core region and a Newtonian fluid model in the periphery region. The governing partial differential equations are derived for each region by using mass and momentum conservation equations. In order to facilitate numerical solutions, the derived differential equations are nondimensionalized. A well-tested explicit finite-difference method (FDM) which is forward in time and central in space is employed for the solution of a nonlinear initial boundary value problem corresponding to each region. Validation of the FDM computations is achieved with a variational finite element method algorithm. The influences of the emerging geometric and rheological parameters on axial velocity, resistance impedance and wall shear stress are displayed graphically. The instantaneous patterns of streamlines are also presented to illustrate the global behaviour of the blood flow. The simulations are relevant to haemodynamics of small blood vessels and capillary transport, wherein rheological effects are dominant. [ABSTRACT FROM PUBLISHER]