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R. Ponalagusamy 한국유변학회 2017 Korea-Australia rheology journal Vol.29 No.2
The primary concern of the present investigation is to study blood flow in a porous catheterized artery with an axially asymmetric and radially symmetric stenosis (constriction). In the present study, blood is characterized as a two-fluid system containing a cell-rich zone of suspension of blood cells described to be a particle-fluid suspension (Jeffrey fluid) and a cell-free plasma (Newtonian fluid) layer near the wall. The systematic expressions for flow characteristics such as fluid phase and particle phase velocities, flow rate, wall shear stress, resistive force, and frictional forces on walls of arterial stenosis and catheter are derived. It is recorded that the wall shear stress, flow resistance, and frictional forces are found to be increased with catheter size, red cell concentration, and slip parameter. When blood obeys the law of constitutive equation of a Jeffrey fluid, the flowing blood experiences lesser wall shear stress, flow resistance and frictional forces as compared to the case of blood being categorized as a Newtonian fluid. The increase in Darcy number, blood rheology as Jeffrey fluid, and the presence of peripheral plasma layer near the wall serves to reduce substantially the values of the flow characteristics (wall shear stress, flow resistance and frictional forces).
R. Ponalagusamy,D. Murugan 한국유변학회 2022 Korea-Australia rheology journal Vol.34 No.1
We investigated the effects of silica nanoparticles (SiNPs) on the rheological properties and microstructures of polyvinyl alcohol (PVA)/silver nanowire (AgNW) suspensions. For PVA/AgNW suspensions without SiNPs, rheological percolation threshold was calculated using storage modulus determined by small amplitude oscillatory shear (SAOS) tests. Results from SAOS tests revealed that PVA/AgNW suspensions had two transition concentrations, which led to different structure developments. Storage modulus from large amplitude oscillatory shear (LAOS) tests showed double-step strain softening behavior at all AgNW concentrations tested, and elastic stress components, also obtained by LAOS tests, exhibited trends similar to storage modulus development. Furthermore, two distinguishable structures were observed when large strain amplitude shear was applied. When SiNPs were added to PVA/AgNW suspensions, the rheological properties of PVA/AgNW suspensions from SAOS tests increased. LAOS results showed storage modulus and elastic stress components of PVA/AgNW suspensions were dependent on AgNW concentration. Doublestep strain softening disappeared for PVA/AgNW suspensions containing SiNPs at low AgNW concentrations, whereas at high AgNW concentrations double-step strain softening behavior was observed.
R. Ponalagusamy,S. Priyadharshini 한국유변학회 2017 Korea-Australia rheology journal Vol.29 No.4
The present study investigates the pulsatile flow of Casson nanofluid through an inclined and stenosed artery with tapering in the presence of magnetic field and periodic body acceleration. The iron oxide nanoparticles are allowed to flow along with it. The governing equations for the flow of Casson fluid when the artery is tapered slightly having mild stenosis are highly non-linear and the momentum equations for temperature and concentration are coupled and are solved using finite difference numerical schemes in order to find the solutions for velocity, temperature, concentration, wall shear stress, and resistance to blood flow. The aim of the present study is to analyze the effects of flow parameters on the flow of nanofluid through an inclined arterial stenosis with tapering. These effects are represented graphically and concluded that the wall shear stress profiles enhance with increase in yield stress, magnetic field, thermophoresis parameter and decreases with Brownian motion parameter, local temperature Grashof number, local nanoparticle Grashof number. The significance of the model is the existence of yield stress and it is examined that when the rheology of blood changes from Newtonian to Casson fluid, the percentage of decrease in the flow resistance is higher with respect to the increase in the parameters local temperature Grashof number, local nanoparticle Grashof number, Brownian motion parameter, and Prandtl number. It is pertinent to observe that increase in the Brownian motion parameter leads to increment in concentration and temperature profiles. It is observed that the concentration of nanoparticles decreases with increase in the value of thermophoresis parameter.
R. Ponalagusamy 한국유변학회 2016 Korea-Australia rheology journal Vol.28 No.3
The present article concerns the problem of blood flow through an artery with an axially asymmetric stenosis (constriction). The two-layered macroscopic model consisting of a cell-rich core of suspension of all the erythrocytes described as a particle-fluid suspension (Jeffrey fluid) and a peripheral zone of cell-free plasma (Newtonian fluid). The analytical expressions for flow characteristics such as fluid phase and particle phase velocities, flow rate, wall shear stress, and resistive force are obtained. It is of interest to mention that the magnitudes of wall shear stress and flow resistance increase with red cell concentration but the flow resistance decreases with increasing shape parameter. One of the important observations is that when blood behaves like a Jeffrey fluid, the flowing blood experiences lesser wall shear stress and flow resistance than in the case of blood being characterized as a Newtonian fluid in both the particle-fluid suspension and particle- free flow studies. The rheology of blood as Jeffrey fluid and the introduction of plasma layer thickness cause significant reduction in the magnitudes of the flow characteristics.
CHANDRU, M.,PONALAGUSAMY, R.,ALPHONSE, P.J.A. The Korean Society for Computational and Applied M 2017 Journal of applied mathematics & informatics Vol.35 No.1
A new fifth-order weighted Runge-Kutta algorithm based on heronian mean for solving initial value problem in ordinary differential equations is considered in this paper. Comparisons in terms of numerical accuracy and size of the stability region between new proposed Runge-Kutta(5,5) algorithm, Runge-Kutta (5,5) based on Harmonic Mean, Runge-Kutta(5,5) based on Contra Harmonic Mean and Runge-Kutta(5,5) based on Geometric Mean are carried out as well. The problems, methods and comparison criteria are specified very carefully. Numerical experiments show that the new algorithm performs better than other three methods in solving variety of initial value problems. The error analysis is discussed and stability polynomials and regions have also been presented.
M. Chandru,R. Ponalagusamy,P.J.A. ALPHONSE 한국전산응용수학회 2017 Journal of applied mathematics & informatics Vol.35 No.1
A new fth-order weighted Runge-Kutta algorithm based on heronian mean for solving initial value problem in ordinary dierential equations is considered in this paper. Comparisons in terms of numerical accuracy and size of the stability region between new proposed Runge- Kutta(5,5) algorithm, Runge-Kutta (5,5) based on Harmonic Mean, Runge- Kutta(5,5) based on Contra Harmonic Mean and Runge-Kutta(5,5) based on Geometric Mean are carried out as well. The problems, methods and comparison criteria are specied very carefully. Numerical experiments show that the new algorithm performs better than other three methods in solving variety of initial value problems. The error analysis is discussed and stability polynomials and regions have also been presented.
Ashis Kumar Roy,Apu Kumar Saha,R. Ponalagusamy,Sudip Debnath 한국유변학회 2020 Korea-Australia rheology journal Vol.32 No.4
The mathematical model of hydrodynamic dispersion through a porous medium is developed in the presence of transversely applied magnetic fields and axial harmonic pressure gradient. The solute introduce into the flow is experienced a first-order chemical reaction with flowing liquid. The dispersion coefficient is numerically determined using Aris’s moment equation of solute concentration. The numerical technique employed here is a finite difference implicit scheme. Dispersion coefficient behavior with Darcy number, Hartmann number and bulk flow reaction parameter is investigated. This study highlighted that the dependency of Hartmann number and Darcy number on dispersion shows different natures in different ranges of these parameters.