Adetunji Adeniyan | University of Lagos,Nigeria (original) (raw)

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Papers by Adetunji Adeniyan

We analyze the simultaneous effects of thermal and concentrations on a mixed convection boundary ... more We analyze the simultaneous effects of thermal and concentrations on a mixed convection boundary layer flow over a permeable surface under convective surface boundary condition in the presence of heat generation and thermal radiation. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically using Maple 14 which uses a fifth-sixth order Runge–Kutta-Fehlberg algorithm together with shooting method. It is seen that as buoyancy force parameter N and the Biot number Bi increases, the skin-friction coefficient, heat transfer rate and the mass transfer rate also increases. It is also noticed that increasing the thermal radiation and the internal heat generation parameters, it enhances the skin-friction coefficient and the mass transfer rate while it decreases the heat transfer rate at the wall surface. The heat generation parameters γ enhances the skinfriction coefficient and the mass transfer rate. Similarly, the embedded flow parameters have significant influence on the double-diffusive convection and that heat generation and radiation parameters enhances the skin-friction coefficient and mass transfer while it reduces the heat transfer rate.

Analysis is conducted on the effects of thermal diffusion and diffusion thermo on unsteady mixed ... more Analysis is conducted on the effects of thermal diffusion and diffusion thermo on unsteady mixed convection flow past a porous plate moving through a binary mixture in the presence of radiative heat transfer and nth-order Arrhenius type of irreversible chemical reaction by taking into account the magnetic field and viscous dissipation. Assuming an optically thin radiation fluid and using the similarity variables, the governing non-linear partial differential equations are transformed into a set of coupled non-linear ordinary differential equations, which are solved numerically by applying shooting iteration technique together with sixth-order Runge-Kutta integration scheme for better accuracy. A comparison with previous work is made and the results are consistent. Numerical calculations of the local skin friction coefficient, the local Nusselt number and the local Sherwood number as well as velocity, temperature and concentration profiles of the fluid, are presented for different physical parameters. It was found that: (i) for fluids with light-medium molecular weight (H 2 , air), thermal diffusion and diffusion thermo effects should not be neglected; and (ii) the magnetic field and Eckert number largely govern the rate heat transfer in the boundary and the velocity boundary layer thickness.

This paper considers the effects of thermogenesis parameters and biot numbers on the temperature ... more This paper considers the effects of thermogenesis parameters and biot numbers on the temperature of the human head. A non heat conduction model was considered for this work and its solution was graphically analysed .The results show that when the thermogenesis heat parameter is zero, then the temperature of the human head is at set point. Also, an increase in the thermogenesis heat or metabolic parameters may lead to an increase in the temperature of the human head. Moreover, the temperature of the human head is higher at the core and decreases transversely with minimum value at the periphery. The results also show that the temperature of the human head increases or decreases as the biot number decreases or increases with increase or decrease in thermogenesis heat parameter.

Beiträge aus der Plasmaphysik, 1984

The dynamic instability in a horizontal layer of a rotating compressible plasma of variable densi... more The dynamic instability in a horizontal layer of a rotating compressible plasma of variable density has been investigated to examine the influence of the simultaneous presence of the effects of Hall currents and finite magnetic resistivity. The linearized stability analysis has been carried out through the normal mode technique. 33y making use of the existence of a variational principle which is shown to characterize the problem, proper solutions have been obtained for a semiinfinite plasma in which there is an exponential density gradient along the vertical. The dispersion relation obtained has been solved numerically and it is found that both the resistivity and the H~l l currents have a destabilizing influence as the growth rate of the unstable disturbances increases with increasing values of the parameters characterizing these effects. On the other hand, the Coriolis forces are found to have a stabilizing influence for in this case the growth rate decreases with increasing rotation.

Applied and Computational Mathematics, 2014

The transient two-dimensional MHD boundary-layer stagnation point flow with heat and mass transfe... more The transient two-dimensional MHD boundary-layer stagnation point flow with heat and mass transfer in a saturated porous medium is presented here by taking into account the transient dispersion of a pollutant spewed by an external source in the presence of a uniform transverse magnetic field and stress (pressure) work. The laminar flow of viscous incompressible and electrically conducting fluid encompassing a convectively heated stationary permeable sheet is assumed to be described in terms of Darcian law. The nonlinear governing partial differential equations obtained are converted into ordinary differential equations by means of appropriate similarity transformations and consequently solved numerically using the forth order Runge-Kutta method with a shooting technique and depicted graphically for some pertinent values of the physical parameters embedded in the flow model. In addition, the skin-friction coefficient, the heat and pollution mass concentration rates are sorted out in tabular form, analyzed and discussed. We opine that findings of this present study will be found useful for environmental systems in pollution control and ventilation, and serve as complementary reference for researchers.

Analysis is presented for the influence of chemical reaction, thermal radiation, thermal-diffusio... more Analysis is presented for the influence of chemical reaction, thermal radiation, thermal-diffusion, diffusion-thermo on hydromagnetic free convection with heat and mass transfer past a vertical plate with suction/injection. Similarity solutions are obtained using suitable transformations. The ordinary differential equations are then solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with sixth order Runge-Kutta integration scheme. The numerical results for some special cases have been compared with those obtained by M. S. Alam et al. [Int. J. Appl. Mech. Eng. 11, No. 3, 535–545 (2006; Zbl 1195.76364)] and are found in very good agreement. For fluids of medium molecular weight (H 2 , air), the profiles of the dimensionless velocity, temperature and concentration distributions are shown graphically for various values of suction parameter f w , Dufour number Df, Soret number Sr, chemical reaction parameter γ, order of reactions n, radiation paramete...

The thermal-diffusion and diffusion-thermo effects on the heat and mass transfer characteristics ... more The thermal-diffusion and diffusion-thermo effects on the heat and mass transfer characteristics of free convection past a moving vertical plate embedded in a porous medium in the presence of magnetic field, blowing/suction and thermal radiation is investigated. Using appropriate similarity variables and boundary-layer approximations, the fluid equations for continuity, momentum, energy and chemical species concentration balance governing the problem are formulated. These equations are solved numerically by using the most effective Newton–Raphson shooting method along with sixth-order Runge–Kutta integration algorithm. . It was found that the fluid temperature increases while both the fluid velocity and chemical species concentration decreases as Soret number decreases and Dufour number increases. Moreover, both magnetic field and porous medium permeability parameters have a weakening effect on the local skin friction coefficient, local Nusselt number and the local Sherwood number. ...

We analyze the simultaneous effects of thermal and concentrations on a mixed convection boundary ... more We analyze the simultaneous effects of thermal and concentrations on a mixed convection boundary layer flow over a permeable surface under convective surface boundary condition in the presence of heat generation and thermal radiation. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically using Maple 14 which uses a fifth-sixth order Runge–Kutta-Fehlberg algorithm together with shooting method. It is seen that as buoyancy force parameter N and the Biot number Bi increases, the skin-friction coefficient, heat transfer rate and the mass transfer rate also increases. It is also noticed that increasing the thermal radiation and the internal heat generation parameters, it enhances the skin-friction coefficient and the mass transfer rate while it decreases the heat transfer rate at the wall surface. The heat generation parameters γ enhances the skinfriction coefficient and the mass transfer rate. Similarly, the embedded flow parameters have significant influence on the double-diffusive convection and that heat generation and radiation parameters enhances the skin-friction coefficient and mass transfer while it reduces the heat transfer rate.

Analysis is conducted on the effects of thermal diffusion and diffusion thermo on unsteady mixed ... more Analysis is conducted on the effects of thermal diffusion and diffusion thermo on unsteady mixed convection flow past a porous plate moving through a binary mixture in the presence of radiative heat transfer and nth-order Arrhenius type of irreversible chemical reaction by taking into account the magnetic field and viscous dissipation. Assuming an optically thin radiation fluid and using the similarity variables, the governing non-linear partial differential equations are transformed into a set of coupled non-linear ordinary differential equations, which are solved numerically by applying shooting iteration technique together with sixth-order Runge-Kutta integration scheme for better accuracy. A comparison with previous work is made and the results are consistent. Numerical calculations of the local skin friction coefficient, the local Nusselt number and the local Sherwood number as well as velocity, temperature and concentration profiles of the fluid, are presented for different physical parameters. It was found that: (i) for fluids with light-medium molecular weight (H 2 , air), thermal diffusion and diffusion thermo effects should not be neglected; and (ii) the magnetic field and Eckert number largely govern the rate heat transfer in the boundary and the velocity boundary layer thickness.

This paper considers the effects of thermogenesis parameters and biot numbers on the temperature ... more This paper considers the effects of thermogenesis parameters and biot numbers on the temperature of the human head. A non heat conduction model was considered for this work and its solution was graphically analysed .The results show that when the thermogenesis heat parameter is zero, then the temperature of the human head is at set point. Also, an increase in the thermogenesis heat or metabolic parameters may lead to an increase in the temperature of the human head. Moreover, the temperature of the human head is higher at the core and decreases transversely with minimum value at the periphery. The results also show that the temperature of the human head increases or decreases as the biot number decreases or increases with increase or decrease in thermogenesis heat parameter.

Beiträge aus der Plasmaphysik, 1984

The dynamic instability in a horizontal layer of a rotating compressible plasma of variable densi... more The dynamic instability in a horizontal layer of a rotating compressible plasma of variable density has been investigated to examine the influence of the simultaneous presence of the effects of Hall currents and finite magnetic resistivity. The linearized stability analysis has been carried out through the normal mode technique. 33y making use of the existence of a variational principle which is shown to characterize the problem, proper solutions have been obtained for a semiinfinite plasma in which there is an exponential density gradient along the vertical. The dispersion relation obtained has been solved numerically and it is found that both the resistivity and the H~l l currents have a destabilizing influence as the growth rate of the unstable disturbances increases with increasing values of the parameters characterizing these effects. On the other hand, the Coriolis forces are found to have a stabilizing influence for in this case the growth rate decreases with increasing rotation.

Applied and Computational Mathematics, 2014

The transient two-dimensional MHD boundary-layer stagnation point flow with heat and mass transfe... more The transient two-dimensional MHD boundary-layer stagnation point flow with heat and mass transfer in a saturated porous medium is presented here by taking into account the transient dispersion of a pollutant spewed by an external source in the presence of a uniform transverse magnetic field and stress (pressure) work. The laminar flow of viscous incompressible and electrically conducting fluid encompassing a convectively heated stationary permeable sheet is assumed to be described in terms of Darcian law. The nonlinear governing partial differential equations obtained are converted into ordinary differential equations by means of appropriate similarity transformations and consequently solved numerically using the forth order Runge-Kutta method with a shooting technique and depicted graphically for some pertinent values of the physical parameters embedded in the flow model. In addition, the skin-friction coefficient, the heat and pollution mass concentration rates are sorted out in tabular form, analyzed and discussed. We opine that findings of this present study will be found useful for environmental systems in pollution control and ventilation, and serve as complementary reference for researchers.

Analysis is presented for the influence of chemical reaction, thermal radiation, thermal-diffusio... more Analysis is presented for the influence of chemical reaction, thermal radiation, thermal-diffusion, diffusion-thermo on hydromagnetic free convection with heat and mass transfer past a vertical plate with suction/injection. Similarity solutions are obtained using suitable transformations. The ordinary differential equations are then solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with sixth order Runge-Kutta integration scheme. The numerical results for some special cases have been compared with those obtained by M. S. Alam et al. [Int. J. Appl. Mech. Eng. 11, No. 3, 535–545 (2006; Zbl 1195.76364)] and are found in very good agreement. For fluids of medium molecular weight (H 2 , air), the profiles of the dimensionless velocity, temperature and concentration distributions are shown graphically for various values of suction parameter f w , Dufour number Df, Soret number Sr, chemical reaction parameter γ, order of reactions n, radiation paramete...

The thermal-diffusion and diffusion-thermo effects on the heat and mass transfer characteristics ... more The thermal-diffusion and diffusion-thermo effects on the heat and mass transfer characteristics of free convection past a moving vertical plate embedded in a porous medium in the presence of magnetic field, blowing/suction and thermal radiation is investigated. Using appropriate similarity variables and boundary-layer approximations, the fluid equations for continuity, momentum, energy and chemical species concentration balance governing the problem are formulated. These equations are solved numerically by using the most effective Newton–Raphson shooting method along with sixth-order Runge–Kutta integration algorithm. . It was found that the fluid temperature increases while both the fluid velocity and chemical species concentration decreases as Soret number decreases and Dufour number increases. Moreover, both magnetic field and porous medium permeability parameters have a weakening effect on the local skin friction coefficient, local Nusselt number and the local Sherwood number. ...