Browsing by Author "Makinde, Oluwole Daniel"
Now showing 1 - 16 of 16
Results Per Page
- Item3D simulation of incompressible Poiseuille flow through 180° curved duct of square cross-section under effect of thermal buoyancy(Budapest University of Technology and Economics, 2019-08-04) Mokeddem, Mourad; Laidoudi, Houssem; Makinde, Oluwole Daniel; Bouzit, MohamedIn this paper, three-dimensional numerical simulations are carried out to investigate and analyze the gradual effects of thermal buoyancy strength on laminar flow of an incompressible viscous fluid and heat transfer rate inside a 180° curved channel of square cross-section. The governing equations of continuity, momentum and energy balance are obtained and solved numerically using finite volume method. The effect of Dean number, De, and Richardson number, Ri, on dimensionless velocity profiles and Nusselt number are examined for the conditions: De = 125 to 150, Ri = 0 to 2 at Pr = 1. The mean results are illustrated in terms of streamline and isotherm contours to interpret the flow behaviors and its effect on heat transfer rate. Dimensionless velocity profiles and the local Nusselt number at the angle 0° and 90° are presented and discussed. Also, the average Nusselt number on surfaces of curved duct is computed. The obtained results showed that by adding thermal buoyancy to computed domain, some early Dean vortices are observed at the angle 0° and new sort are observed at 90°. Furthermore, increase in Dean number increases the heat transfer rate. In other hand, increase in Richardson number decreases the average Nusselt number of 180° curved duct.
- ItemChemically reacting on MHD boundary-layer flow of nanofluids over a non-linear stretching sheet with heat source/sink and thermal radiation(Thermal Science, 2018) Makinde, Oluwole Daniel; Mabood, Fazle; Ibrahim, Mohammed S.In this paper, steady 2-D MHD free convective boundary-layer flows of an electrically conducting nanofluid over a non-linear stretching sheet taking into account the chemical reaction and heat source/sink are investigated. The governing equations are transformed into a system of non-linear ODE using suitable similarity transformations. Analytical solution for the dimensionless velocity, temperature, concentration, skin friction coefficient, heat and mass transfer rates are obtained by using homotopy analysis method. The obtained results show that the flow field is substantially influenced by the presence of chemical reaction, radiation, and magnetic field.
- ItemCombined effect of buoyancy force and Navier slip on MHD flow of a nanofluid over a convectively heated vertical porous plate(Hindawi, 2013) Mutuku-Njane, Winifred Nduku; Makinde, Oluwole DanielWe examine the effect of magnetic field on boundary layer flow of an incompressible electrically conducting water-based nanofluids past a convectively heated vertical porous plate with Navier slip boundary condition. A suitable similarity transformation is employed to reduce the governing partial differential equations into nonlinear ordinary differential equations, which are solved numerically by employing fourth-order Runge-Kutta with a shooting technique. Three different water-based nanofluids containing copper (Cu), aluminium oxide (Al2O3), and titanium dioxide (TiO2) are taken into consideration. Graphical results are presented and discussed quantitatively with respect to the influence of pertinent parameters, such as solid volume fraction of nanoparticles (), magnetic field parameter (Ha), buoyancy effect (Gr), Eckert number (Ec), suction/injection parameter (), Biot number (Bi), and slip parameter (β), on the dimensionless velocity, temperature, skin friction coefficient, and heat transfer rate.
- ItemEntropy generation in a couple stress fluid flow through a vertical channel filled with saturated porous media(MDPI, 2013-10-25) Makinde, Oluwole Daniel; Eegunjobi, Adetayo SamuelThe present work investigates numerically the inherent irreversibility in a steady flow of a couple stress fluid through a vertical channel packed with saturated porous substances. The First and Second Laws of Thermodynamics are applied to analyze the problem. The nonlinear governing equations in Cartesian coordinates are obtained and solved numerically using shooting methods together with a Runge-Kutta Fehlberg integration scheme. The entropy generation number is computed by utilizing the velocity and temperature profiles. The effects of various physical parameters on the flow and heat transfer characteristics, as well as entropy generation rates and Bejan number, are investigated through graphs.
- ItemImpact of second order slip and non-uniform suction on non-linear stagnation point flow of alumina-water nanofluid over electromagnetic sheet(International Information and Engineering Technology Association, 2019) Nayak, Manoj Kumar; Zeeshan, Ahmad; Pervaiz, Zeshan; Makinde, Oluwole DanielThe purpose of the present article is to study the influence of second order slip and variable suction on non-linear stagnation point flow of Alumina-water nanofluid past an electromagnetic sheet embedded in a porous medium. A simulation model was established through hybrid Homotopy Analysis Method (HAM) and Genetic Algorithm Method (GAM). Through this it was found that favorable pressure gradient and modified Hartmann number yield accelerated fluid motion while porous matrix and first order slip result in decelerated flow over stationary/moving electromagnetic sheet. The finding of this research may serve as greater cooling agent due to more heat transfer rate from the electromagnetic sheet subject to favorable pressure gradient.
- ItemImpact of thermophoretic transport of Al₂O₃ nanoparticles on viscoelastic flow of oil-based nanofluid over a porous exponentially stretching surface with activation energy(Institute of Fundamental Technological Research, 2019) Etwire, Christian John; Seini, Ibrahim Yakubu; Rabiu, Musah; Makinde, Oluwole DanielThe influence of thermophoretic transport of Al₂O₃ nanoparticles on heat and mass trans- fer in viscoelastic flow of oil-based nanofluid past porous exponentially stretching surface with activation energy has been examined. Similarity technique was employed to transform the gov- erning partial differential equations into a coupled fourth-order ordinary differential equations which were reduced to a system of first-order ordinary differential equations and then solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The re- sults for various controlling parameters were tabulated and graphically illustrated. It was found that the thermophoretic transport of Al₂O₃ nanoparticles did not affect the rate of flow and heat transfer at the surface but it affected the rate of mass transfer of the nanofluid which decayed the solutal boundary layer thickness. This study also revealed that activation energy retards the rate of mass transfer which causes a thickening of the solutal boundary layer.
- ItemInfluence of rotation on transversely isotropic piezoelectric rod coated with a thin film(Polish Academy of Sciences, 2018) Selvamani, Rajendran; Makinde, Oluwole DanielIn this paper, the influence of rotation on axisymmetric waves of a piezoelectric rod coated with a thin film is studied using constitutive form linear theory elasticity and piezo-electric equations. Potential functions are introduced to uncouple the equations of motion in radial and axial directions. The surface area of the rod is coated by a perfectly conducting material. The frequency equations are obtained for longitudinal and flexural modes of vibration and are studied numerically for PZT-4 ceramics. The computed non-dimensional frequency, phase velocity, relative frequency shift, electromechanical coupling and electric displacement are presented in the form of dispersion curves. This type of study is important in the construction of rotating sensors and gyroscope.
- ItemA mathematical model for coinfection of listeriosis and anthrax diseases(Hindawi, 2018) Osman, Shaibu; Makinde, Oluwole DanielListeriosis and Anthrax are fatal zoonotic diseases caused by Listeria monocytogene and Bacillus Anthracis, respectively. In this paper, we proposed and analysed a compartmental Listeriosis-Anthrax coinfection model describing the transmission dynamics of Listeriosis and Anthrax epidemic in human population using the stability theory of differential equations. Our model revealed that the disease-free equilibrium of the Anthrax model only is locally stable when the basic reproduction number is less than one. Sensitivity analysis was carried out on the model parameters in order to determine their impact on the disease dynamics. Numerical simulation of the coinfection model was carried out and the results are displayed graphically and discussed. We simulate the Listeriosis-Anthrax coinfection model by varying the human contact rate to see its effects on infected Anthrax population, infected Listeriosis population, and Listeriosis-Anthrax coinfected population.
- ItemMHD slip flow of Casson fluid along a nonlinear permeable stretching cylinder saturated in a porous medium with chemical reaction, viscous dissipation, and heat generation/absorption(MDPI, 2019) Ullah, Imran; Alkanhal, Tawfeeq Abdullah; Shafie, Sharidan; Nisar, Kottakkaran Sooppy; Khan, Ilyas; Makinde, Oluwole DanielThe aim of the present analysis is to provide local similarity solutions of Casson fluid over a non-isothermal cylinder subject to suction/blowing. The cylinder is placed inside a porous medium and stretched in a nonlinear way. Further, the impact of chemical reaction, viscous dissipation, and heat generation/absorption on flow fields is also investigated. Similarity transformations are employed to convert the nonlinear governing equations to nonlinear ordinary differential equations, and then solved via the Keller box method. Findings demonstrate that the magnitude of the friction factor and mass transfer rate are suppressed with increment in Casson parameter, whereas heat transfer rate is found to be intensified. Increase in the curvature parameter enhanced the flow field distributions. The magnitude of wall shear stress is noticed to be higher with an increase in porosity and suction/blowing parameters.
- ItemMHD variable viscosity mixed convection of nanofluid in a microchannel with permeable walls(CSIR-NIScPR, 2020) Kefene, Mesfin Zewde; Makinde, Oluwole Daniel; Enyadene, Lemi GutaIn this study, we examine the combined effects of buoyancy forces, pressure gradient, thermophoresis, Brownian motion, variable viscosity of nanofluid flow in a microchannel with suction and injection in the presence of uniform magnetic field imposed in cross-wise direction. It is assumed that the dynamic viscosity of the nanofluid is related with temperature exponentially and that the vertical parallel-plates temperature is held asymmetrically. Applying similarity transformation, the governing system of partial differential equations (PDEs) are transformed into a set of non-dimensional nonlinear partial differential equations whose solutions are obtained numerically by semi-discretization centered finite difference method along with Runge-Kutta Fehlberg integration technique scheme. Qualitative description of graphical results depicting the effect of thermophysical parameters on the dimensionless velocity, temperature, nanoparticles concentration, skin friction, Nusselt number and Sherwood number are presented.
- ItemModelling and optimal control of pneumonia disease with cost-effective strategies(Informa UK Limited, trading as Taylor & Francis Group, 2017) Tilahun, Getachew Teshome; Makinde, Oluwole Daniel; Malonza, DavidWe propose and analyse a nonlinear mathematical model for the transmission dynamics of pneumonia disease in a population of varying size. The deterministic compartmental model is studied using stability theory of differential equations. The effective reproduction number is obtained and also the asymptotic stability conditions for the disease free and as well as for the endemic equilibria are established. The possibility of bifurcation of the model and the sensitivity indices of the basic reproduction number to the key parameters are determined. Using Pontryagin's maximum principle, the optimal control problem is formulated with three control strategies: namely disease prevention through education, treatment and screening. The cost-effectiveness analysis of the adopted control strategies revealed that the combination of prevention and treatment is the most cost-effective intervention strategies to combat the pneumonia pandemic. Numerical simulation is performed and pertinent results are displayed graphically.
- ItemModelling and optimal control of typhoid fever disease with cost-effective strategies(Hindawi Publishing Corporation, 2017-09) Tilahun, Getachew Teshome; Makinde, Oluwole Daniel; Malonza, DavidWe propose and analyze a compartmental nonlinear deterministic mathematical model for the typhoid fever outbreak and optimal control strategies in a community with varying population.The model is studied qualitatively using stability theory of differential equations and the basic reproductive number that represents the epidemic indicator is obtained from the largest eigenvalue of the next-generation matrix. Both local and global asymptotic stability conditions for disease-free and endemic equilibria are determined. The model exhibits a forward transcritical bifurcation and the sensitivity analysis is performed.The optimal control problem is designed by applying Pontryagin maximum principle with three control strategies, namely, the prevention strategy through sanitation, proper hygiene, and vaccination; the treatment strategy through application of appropriate medicine; and the screening of the carriers. The cost functional accounts for the cost involved in prevention, screening, and treatment together with the total number of the infected persons averted. Numerical results for the typhoid outbreak dynamics and its optimal control revealed that a combination of prevention and treatment is the best cost-effective strategy to eradicate the disease.
- ItemNew developments in fluid mechanics and its engineering applications(Hindawi, 2013) Makinde, Oluwole Daniel; Khan, Waqar Ahmed; Chinyoka, TirivanhuFluid mechanics is an active field of research with many unsolved or partially solved problems in science and engineering. Fluid mechanics can be mathematically complex. Sometimes the problems can best be solved by numerical methods, typically using computers. Fluids have the ability to transport matter and its properties as well as transmit force; therefore fluidmechanics is a subject that is particularly open to cross-fertilization with other sciences and disciplines of engineering. The subject of fluidmechanics is highly relevant in such domains as mechanical, chemical, petrochemical, civil, metallurgical, biological, and ecological engineering.
- ItemOptimal control and cost effectiveness analysis for Newcastle disease eco-epidemiological model in Tanzania(Informa UK Limited, trading as Taylor & Francis Group, 2017) Hugo, Alfred; Makinde, Oluwole Daniel; Kumar, Santosh; Chibwana, Fred F.In this paper, a deterministic compartmental eco- epidemiological model with optimal control of Newcastle disease (ND) in Tanzania is proposed and analysed. Necessary conditions of optimal control problem were rigorously analysed using Pontryagin’s maximum principle and the numerical values of model parameters were estimated using maximum likelihood estimator. Three control strategies were incorporated such as chicken vaccination (preventive), human education campaign and treatment of infected human (curative) and its’ impact were graphically observed. The incremental cost effectiveness analysis technique used to determine the most cost effectiveness strategy and we observe that combination of chicken vaccination and human education campaign strategy is the best strategy to implement in limited resources. Therefore,NDcan be controlled if the farmers will apply chicken vaccination properly and well in time.
- ItemParameter estimation and sensitivity analysis of Dysentery diarrhea epidemic model(Hindawi, 2019) Berhe, Hailay Weldegiorgis; Makinde, Oluwole Daniel; Theuri, David MwangiIn this paper, dysentery diarrhea deterministic compartmental model is proposed. The local and global stability of the disease- free equilibrium is obtained using the stability theory of differential equations. Numerical simulation of the system shows that the backward bifurcation of the endemic equilibrium exists for 𝑅₀ > 1. The system is formulated asa standard nonlinear least squares problem to estimate the parameters. The estimated reproduction number, based on the dysentery diarrhea disease data for Ethiopia in 2017, is 𝑅₀ = 1.1208. This suggests that elimination of the dysentery disease from Ethiopia is not practical. A graphical method is used to validate the model. Sensitivity analysis is carried out to determine the importance of model parameters in the disease dynamics. It is found out that the reproduction number is the most sensitive to the effective transmission rate of dysentery diarrhea (𝛽). It is also demonstrated that control of the effective transmission rate is essential to stop the spreading of the disease.
- ItemThermal decomposition analysis in a sphere of combustible materials(Sage, 2017) Lebelo, Ramoshweu Solomon; Makinde, Oluwole Daniel; Chinyoka, T.In this article, we look at spontaneous combustion due to exothermic chemical reaction taking place within a stockpile of combustible material. The model includes mass and energy balance equations in a spherical domain. The complicated chemical reaction is simplified by considering a one-dimensional process. The differential equations governing the problem are solved using semi-implicit finite difference method. The effects of kinetic parameters embedded within the system are analyzed and the results are expressed graphically and discussed accordingly.