Cédric Gervais Njingang Ketchate, Oluwole Daniel Makinde, Pascalin Tiam Kapen and Didier Fokwa
This paper aims to investigate the hydrodynamic instability properties of a mixed convection flow of nanofluid in a porous channel.
Abstract
Purpose
This paper aims to investigate the hydrodynamic instability properties of a mixed convection flow of nanofluid in a porous channel.
Design/methodology/approach
The treated single-phase nanofluid is a suspension consisting of water as the working fluid and alumina as a nanoparticle. The anisotropy of the porous medium and the effects of the inclination of the magnetic field are highlighted. The effects of viscous dissipation and thermal radiation are incorporated into the energy equation. The eigenvalue equation system resulting from the stability analysis is processed numerically by the spectral collocation method.
Findings
Analysis of the results in terms of growth rate reveals that increasing the volume fraction of nanoparticles increases the critical Reynolds number. Parameters such as the mechanical anisotropy parameter and Richardson number have a destabilizing effect. The Hartmann number, permeability parameter, magnetic field inclination, Prandtl number, wave number and thermal radiation parameter showed a stabilizing effect. The Eckert number has a negligible effect on the growth rate of the disturbances.
Originality/value
Linear stability analysis of Magnetohydrodynamics (MHD) mixed convection flow of a radiating nanofluid in porous channel in presence of viscous dissipation.
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B.J. Gireesha, M. Archana, Prasannakumara B.C., R.S. Reddy Gorla and Oluwole Daniel Makinde
This paper aims to deal with the study of heat and mass transfer on double-diffusive three-dimensional hydromagnetic boundary layer flow of an electrically conducting Casson…
Abstract
Purpose
This paper aims to deal with the study of heat and mass transfer on double-diffusive three-dimensional hydromagnetic boundary layer flow of an electrically conducting Casson nanofluid over a stretching surface. The combined effects of nonlinear thermal radiation, magnetic field, buoyancy forces, thermophoresis and Brownian motion are taken into consideration with convective boundary conditions.
Design/methodology/approach
Similarity transformations are used to reduce the governing partial differential equations into a set of nonlinear ordinary differential equations. The reduced equations were numerically solved using Runge–Kutta–Fehlberg fourth-fifth-order method along with shooting technique.
Findings
The impact of several existing physical parameters such as Casson parameter, mixed convection parameter, regular buoyancy ratio parameter, radiation parameter, Brownian motion parameter, thermophoresis parameter, temperature ratio parameter on velocity, temperature, solutal and nanofluid concentration profiles are analyzed through graphs and tables in detail. It is found that the solutal component increases for Dufour Lewis number, whereas it decreases for nanofluid Lewis number. Moreover, velocity profiles decrease for Casson parameter, while the Nusselt number increases for Biot number, radiation and temperature ratio parameter.
Originality/value
This paper is a new work related to three-dimensional double-diffusive flow of Casson nanofluid with buoyancy and nonlinear thermal radiation effect.
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Vishwanath B. Awati, Oluwole Daniel Makinde and Manjunath Jyoti
The purpose of this paper is to study the laminar boundary layer flow between a stationary nonporous disk and a porous rotating disk, both being immersed in large amount of fluid.
Abstract
Purpose
The purpose of this paper is to study the laminar boundary layer flow between a stationary nonporous disk and a porous rotating disk, both being immersed in large amount of fluid.
Design/methodology/approach
The governing nonlinear momentum equations in cylindrical polar coordinates together with relevant boundary conditions are reduced to a system of coupled nonlinear ordinary differential equations (NODEs) using similarity transformations. The resulting coupled NODEs are solved using computer-extended series solution and homotopy analysis method.
Findings
The analytical solutions are explicitly expressed in terms of recurrence relation for determining the universal coefficients. The nature and location of singularity which restricts the convergence of series is analyzed by using Domb–Sykes plot. Reversion of series is used for the improvement of series. The region of validity of series is extended for much larger values of Reynolds number (R), i.e. R = 6 to 15.
Originality/value
The resulting solutions are compared with earlier works in the literature and are found to be in good agreement.
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Hamza Berrehal, G. Sowmya and Oluwole Daniel Makinde
In heat transfer, fluids and nanoparticles can provide new innovative technologies with potential to adapt the heat transfer fluid’s thermal properties through control over…
Abstract
Purpose
In heat transfer, fluids and nanoparticles can provide new innovative technologies with potential to adapt the heat transfer fluid’s thermal properties through control over particle size, shape and others. This paper aims to examine the effects of spherical and non-spherical (cylinder, disk, platelets, etc.) shapes of silver (Ag) nanoparticles on heat transfer enhancement and inherent irreversibility in hydromagnetic water base nanoliquid flow over a convectively heated stretching sheet with heat generation/absorption.
Design/methodology/approach
Applying suitable similarity constraints, the model partial differential equations are transformed into a set of nonlinear ordinary differential equations. Solutions are obtained analytically via optimal homotopy asymptotic method (OHAM) and numerically via shooting technique coupled with the Runge-Kutta-Fehlberg (RK-F) method.
Findings
The impact of Ag nanoparticle’s shape along with other germane factors, such as Biot number, magnetic field, solid volume fraction and heat source/sink on velocity and thermal profiles, Nusselt number, skin friction coefficient, heat transfer enhancement, rate of entropy generation and irreversibility ratio, are scrutinized via graphical simulations and discussed. This study revealed that cylindrical shape Ag nanoparticles generate high entropy and fluid friction irreversibility, whereas disk shape Ag nanoparticles exhibit high transfer enhancement rate. Moreover, a boost in magnetic field intensity, volume-fraction parameter and Biot number enhances the thermal boundary layer thickness.
Originality/value
The main objective of this work is to examine the different Ag nanoparticles shape effects on the heat transfer enhancement and inherent irreversibility owing to hydromagnetic nanoliquid flow past a convectively heated stretching sheet with heat source/sink, which has not been yet studied. It is hope that this study will bridge the gap in the present literature and serve as impetus to scholars, engineers and industries for more exploration in this direction. The intrinsic nonlinearity of the model equations precludes its exact solution; hence, OHAM and shooting technique coupled with the RK-F method have been used to numerically tackle the problem. Pertinent results are discussed quantitatively and displayed graphically and in tabular form.
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Roopa K.R., Dinesh P.A., Sweeti Yadav and Oluwole Daniel Makinde
The purpose of this study is to examine how fluid flow and heat transfer are affected by the influence of hybrid nanofluids flowing across a stagnation zone of a stretching curved…
Abstract
Purpose
The purpose of this study is to examine how fluid flow and heat transfer are affected by the influence of hybrid nanofluids flowing across a stagnation zone of a stretching curved surface. Stagnation point flow has garnered considerable attention over the past few decades. This is because many technical applications, such as the cooling of nuclear reactors and rotating equipment divisions, rely on stagnation-point flow.
Design/methodology/approach
A thorough analysis is conducted of the impacts of several regulating parameters on fluid flow and thermal performance, including the radiation parameter, heat source parameter, mixed convection parameter, porosity parameter curvature and nanoparticle concentration. The laws governing the field of flow equations are transformed by similarity substitutions into two nonlinear ordinary differential equations, which are then solved numerically using Maple. The MR-Solve technique in the built-in Maple package was used. The MR-Solve technique was used to numerically solve highly coupled ordinary differential equation problems. This approach produced highly precise and consistent results. It also provides the best performance while using a minimum amount of CPU and the shortest phrases.
Findings
The main conclusions of this study show that axial velocity drops, while radial velocity increases as the mixed convection parameter increases. The rate of heat transmission and skin friction is higher for hybrid nanoparticles with volume fraction percentile (0.01–0.03) than for those with volume fraction percentile (0.1–0.3).
Research limitations/implications
Further research on this topic could examine a broader range of parameter values, suction/injection, entropy, mass equation, micropolar fluid, ternary hybrid nanofluid and Newtonian heating flow on a curved stretching surface.
Practical implications
By investigating a novel physical design that combines the various effect with stagnation flow, this study adds value and offers insights and prospective improvements in the discipline of heat fluid mechanics. Mathematical modeling or experimental studies in a variety of multiphysical contexts can be used to achieve this. Heat exchangers, crystalline procedures, microelectronic machines, systems for conserving energy, integrating operations, food manufacturing, climate control, purification and other engineering domains can all benefit from the geometric configurations investigated in this study. The results of this study greatly aid in optimizing thermal performance in a variety of application domains. This study is novel because it compares several volume fraction percentiles.
Originality/value
A stretching curved surface’s stagnation zone is traversed by hybrid nanofluids, offering insights into how curvature affects heat transfer and fluid flow efficiency. The results aid in the design and improvement of the energy transfer efficiencies for a range of commercial and biological purposes. The results offer possibilities for increased efficiency in a range of applications by developing hybrid nanofluid flow control methods and helping to create ideal thermal systems.
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Sanjay Kumar, Kushal Sharma, Oluwole Daniel Makinde, Vimal Kumar Joshi and Salman Saleem
The purpose of this study is to investigate the entropy generation in different nanofluids flow over a vertically moving rotating disk. Unlike the classical Karman flow…
Abstract
Purpose
The purpose of this study is to investigate the entropy generation in different nanofluids flow over a vertically moving rotating disk. Unlike the classical Karman flow, water-based nanofluids have various suspended nanoparticles, namely, Cu, Ag, Al2O3 and TiO2, and the disk is also moving vertically with time-dependent velocity.
Design/methodology/approach
The Keller box technique numerically solves the governing equations after reduction by suitable similarity transformations. The shear stress and heat transport features, along with flow and temperature fields, are numerically computed for different concentrations of the nanoparticles.
Findings
This study is done comparatively in between different nanofluids and for the cases of vertical movement of the disk. It is found that heat transfer characteristics rely not only on considered nanofluid but also on disk movement. Moreover, the upward movement of the disk diminishes the heat-transfer characteristics of the fluid for considered nanoparticles. In addition, for the same group of nanoparticles, an entropy generation study is also performed, and an increasing trend is found for all nanoparticles, with alumina nanoparticles dominating the others.
Originality/value
This research is a novel work on a vertically moving rotating surface for the water-conveying nanoparticle fluid flow with entropy generation analysis. The results were found to be in good agreement in the case of pure fluid.
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S. Sindhu, Gireesha B.J., G. Sowmya and Oluwole Daniel Makinde
This study aims to portray the systematic study of hybrid nanofluid with particle shape effect on significant heat transfer enhancement. The steady flow of hybrid nanoliquid in a…
Abstract
Purpose
This study aims to portray the systematic study of hybrid nanofluid with particle shape effect on significant heat transfer enhancement. The steady flow of hybrid nanoliquid in a microchannel with the aid of porous medium has been considered. The dispersion of copper and Al2O3 in water is taken as hybrid mixture. The impact of thermal radiation, slip length and convective conditions on flow and thermal features are examined numerically.
Design/methodology/approach
The modelled equations are made dimensionless by means of nondimensional entities. The solutions are computed numerically by the implementation of Runge–Kutta-based shooting technique. The results depict that the shape of hybrid mixtures plays a significant role in convective heat transfer. Relevant results on flow velocity, temperature, Nusselt number and friction factor for various physical constraints have been perused. The obtained outcomes are displayed graphically.
Findings
The acquired results depict that Nusselt number augments with Eckert number and solid volume fraction of hybrid nanoparticles, which has a vibrant role in enriching the heat transfer coefficient. Also, it is emphasized that the Nusselt number is larger for blade-shaped nanoparticle compared to other shapes.
Originality/value
The analysis of individual effect of thermal radiation, Joule heating, viscous dissipation and magnetic field on the flow of Cu and Al2O3 hybrid nanofluid through microchannel has vivacious role in augmenting heat transmission. Along with this, the impact of porous medium, shape factor, slip and convective peripheral conditions are also emphasized.
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Daniel Oluwole Makinde and Oswald Franks
The purpose of this paper is to investigate the unsteady magnetohydrodynamic (MHD) Couette flow of an electrically conducting incompressible non-Newtonian third grade reactive…
Abstract
Purpose
The purpose of this paper is to investigate the unsteady magnetohydrodynamic (MHD) Couette flow of an electrically conducting incompressible non-Newtonian third grade reactive fluid with temperature-dependent variable viscosity and thermal conductivity properties under isothermal surface conditions.
Design/methodology/approach
The coupled non-linear partial differential equations for momentum and energy balance governing the transient problem are obtained and tackled numerically using a semi-discretization finite difference technique.
Findings
The effects of various embedded thermophysical parameters on the velocity and temperature fields including skin friction, Nusselt number and thermal stability conditions are presented graphically and discussed quantitatively.
Practical implications
The approach is applicable to modelling the complex physical phenomenon in MHD lubrications that occurs in numerous areas of engineering and industrial processes.
Originality/value
This paper may be of industrial and engineering interest especially in understanding the combined effects of unsteadiness, variable thermophysical properties and magnetic field on the thermal stability condition for a reactive non-Newtonian third grade fluid under Couette flow scenario.
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Oluwole Daniel Makinde and Precious Sibanda
The purpose of this paper is to investigate the effects of first‐order homogeneous chemical reaction on a two‐dimensional boundary layer flow past a vertical stretching surface in…
Abstract
Purpose
The purpose of this paper is to investigate the effects of first‐order homogeneous chemical reaction on a two‐dimensional boundary layer flow past a vertical stretching surface in the presence of internal heat generation.
Design/methodology/approach
Using the Boussinesq and boundary‐layer approximations, the fluid equations for momentum, energy balance and concentration governing the problem are formulated. The governing partial differential equations are transformed using similarity transformations into a set of coupled ordinary differential equations that are solved numerically using a shooting technique and a sixth‐order Runge‐Kutta scheme.
Findings
It was found that for positive values of the buoyancy parameters, the local skin friction and mass transfer coefficients increase with increasing Eckert and Schmidt numbers while the heat transfer coefficient decreases with both Eckert and Schmidt numbers. Both the velocity and temperature profiles increase significantly when the heat generation parameter increases.
Practical implications
Continuous surface heat and mass transfer problems occur naturally in metallurgical process such as in the aerodynamic extrusion of plastic sheets, hot rolling and the cooling of metallic plates in a cooling bath. This work provides a very useful source of information for researchers on this subject.
Originality/value
This paper illustrates the effects of chemical reaction on boundary layer flow past a vertical stretching surface in the presence of internal heat generation.
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Ahmada Omar Ali, Oluwole Daniel Makinde and Yaw Nkansah-Gyekye
The purpose of this paper is to investigate numerically the unsteady MHD Couette flow and heat transfer of viscous, incompressible and electrically conducting nanofluids between…
Abstract
Purpose
The purpose of this paper is to investigate numerically the unsteady MHD Couette flow and heat transfer of viscous, incompressible and electrically conducting nanofluids between two parallel plates in a rotating channel.
Design/methodology/approach
The nanofluid is set in motion by the combined action of moving upper plate, Coriolis force and the constant pressure gradient. The channel rotates in unison about an axis normal to the plates. The nonlinear governing equations for velocity and heat transfer are obtained and solved numerically using semi-discretization, shooting and collocation (bvp4c) techniques together with Runge-Kutta Fehlberg integration scheme.
Findings
Results show that both magnetic field and rotation rate demonstrate significant effect on velocity and heat transfer profiles in the system with Cu-water nanofluid demonstrating the highest velocity and heat transfer efficiency. These numerical results are in excellent agreements with the results obtained by other methods.
Practical implications
This paper provides a very useful source of information for researchers on the subject of hydromagnetic nanofluid flow in rotating systems.
Originality/value
Couette flow of nanofluid in the presence of applied magnetic field in a rotating channel is investigated.