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In the present work, the impact of periodic body acceleration on the unsteady flow of blood in an inclined artery has been investigated. The blood is represented by an incompressible, viscous, non-Newtonian Jeffrey fluid. The artery is assumed to have mild overlapping stenoses inside its lumen. The perturbation method is used to solve the governing nonlinear coupled partial differential equations. Here, the Womersley frequency parameter is considered small enough for blood flow through arteries. Analytic expressions for the wall shear stress, stress at the critical height of stenosis, velocity profile, volumetric flow rate, pressure drop, resistive impedance, and effective viscosity are obtained using the perturbation technique. Regarding different flow parameters, the effects of body acceleration, pulsatility, the non-Newtonian character of blood, and velocity slip are examined and graphically depicted. It is concluded from the present analysis that the flow impedance rises when the stenosis reaches its critical height, but it falls as the velocity slip at the wall increases. It is also observed that when body acceleration increases, flow rate, velocity, and shear stress near the critical height of stenosis all rise, whereas wall shear stress decreases as body acceleration rises. Here, we also analyzed the flow pattern of the non-Newtonian Jeffrey fluid when it passes through the overlapped stenosed artery with the help of streamlines. The results of the present problem have been verified with the previous existing results in the literature. [ABSTRACT FROM AUTHOR]

A mathematical model of physiological pulsatile flow of blood through a stenotic flexible artery in the presence of body acceleration is presented in this paper. Streaming blood is considered as a shear-thinning non-Newtonian fluid as proposed by Yeleswarapu (Evaluation of continuum models for characterizing the constitutive behaviour of blood, Ph.D. thesis, Dept. Mech. Eng., University of Pittsburgh, 1996), and a physiological pulsatile flow rate proposed by Pedrizzetti (J Fluid Mech 310:89–111, 1996) has been taken through the tube. Deformation of vessel wall is modelled as a function of flow rate. This computational study of an idealized model may bring some insights for realistic blood flow through a stenotic artery. The novelty of this work lies in the fact that realistic flow of blood through a stenosed artery has been studied as far as possible and a new idea has been provided to describe the arterial wall motion. Governing equations in cylindrical polar coordinates are solved using stream function–vorticity method. Behaviour of various flow quantities is investigated through a parametric study. It is noted that the degree of constriction and body acceleration have important impacts on the haemodynamic parameters such as wall shear stress, oscillatory shear index, and relative residence time. Increasing body acceleration enhances the peak value of wall shear stress, but reduces the oscillatory shear index and relative residence time. Almost 1/4th increase in length of flow separation is found when Froude number raises its value from 0.1 to 0.5, other parametric values remaining fixed. On the other hand, almost 50% increase in the magnitude of the peak value of wall pressure is found when the amplitude of body acceleration takes a value 0.4 (A = 0.4) compared to the without body acceleration case (A = 0). These results have a significant role. [ABSTRACT FROM AUTHOR]

This study analyses the pulsatile flow of blood through narrow arteries with mild asymmetric stenosis. Blood is modeled as a two-fluid model with the suspension of all the erythrocytes in the core region being treated as Casson fluid and the plasma in the peripheral layer being assumed as Newtonian fluid. Perturbation method is used to solve the resulting coupled implicit system of non-linear partial differential equations. The expressions for shear stress, velocity, wall shear stress, plug core radius, flow rate and resistance to flow are obtained. The effects of pulsatility, stenosis shape parameter, stenosis depth, peripheral layer thickness, body acceleration and non-Newtonian behavior of blood on these flow quantities are discussed. It is noted that the plug core radius and resistance to flow decrease with the increase of the body acceleration and pressure gradient. It is observed that the velocity and flow rate increase with the increase of the peripheral layer thickness and they decrease with the increase of the stenosis shape parameter. It is recorded that the estimates of the mean flow rate of the two-fluid blood flow model are considerably higher than that of the single-fluid blood flow model. It is also noticed that the presence of body acceleration and peripheral layer influences the mean flow rate by increasing their magnitude significantly in the arteries with different radii. [ABSTRACT FROM AUTHOR]

Pulsatile flow of blood through a porous medium has been studied under the influence of periodic body acceleration by considering blood as a couple stress, incompressible, electrically conducting fluid in the presence of magnetic field. An exact solution of the equation of motion is obtained by applying the Laplace and finite Hankel transforms. The expressions for axial velocity, flow rate, fluid acceleration and shear stress have been obtained analytically. The effects of magnetic field, body acceleration and permeability parameter have been discussed with the help of graphs. It is found that the velocity distribution increases with an increase of both body acceleration and permeability of the porous medium, while it decreases as the magnetic parameter increases. [ABSTRACT FROM AUTHOR]

Hjman bodies may occasionally be subjected to high external accelerations. The response of the vascular system under such situations has recently been the subject of several theoretical and experimental studies. However, little work appears to have so far been carried out on the analysis of blood flow in stenosed artery in the presence of body accelerations. In the paper we present a model of blood flow in a partially occluded tube subject to both the pulsatile pressure gradient due to the normal heart action and the periodic body acceleration. Closed-form solutions have been obtained for the instantaneous rate of flow and for the distributions of flow velocity, acceleration and shear stress over the stenosed length. Computational results corresponding to a stenosed carotid artery are presented and discussed. [ABSTRACT FROM AUTHOR]

A theoretical analysis to predict the effects of oscillations under the influence of time-dependent acceleration on the blood flow in arteries is presented. The solutions valid for fast oscillations and a small external acceleration are obtained for the velocity, fluid and stress fields. The computed results show that hgh blood velocities and high shear rates capable of harming the circulation are produced under the influence of such time-dependent acceleration profiles. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of blood flow in large and small arteries under the influence of externally applied periodic oscillations. The solutions for the blood velocity, fluid acceleration and shear stress are obtained. It has been shown that high blood velocity and large shear stresses are produced in large arteries. However, in the case of small arteries the flow is not disturbed. [ABSTRACT FROM AUTHOR]