Ayuba Umar - Academia.edu (original) (raw)

Address: Zaria, Kaduna, Nigeria

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Papers by Ayuba Umar

This study theoretically examines the effects of boundary plate thickness and viscous dissipation... more This study theoretically examines the effects of boundary plate thickness and viscous dissipation on a steady natural convection flow of an incompressible viscous fluid of variable properties. This is due to the fact that several investigations in literature have neglected the thickness and material composition of the boundary plates and as such, their results are either over-determined or under-determined. The viscosity and thermal conductivity of the heat generating/absorbing fluid were assumed to be functions of temperature. Due to the nonlinearity and coupling nature of the governing flow equations, homotopy perturbation method (HPM) has been used to solve the problem. The effects of the thermophysical and flow parameters were captured in graphs and tables. It has been discovered from the study that the velocity profile increases with increase in thermal conductivity. Increase in boundary plate thickness ( d ) was found to boost the fluid flow across the medium while the tempera...

This work concerns a theoretical investigation on the effects of suction/injection, magnetic fiel... more This work concerns a theoretical investigation on the effects of suction/injection, magnetic field, permeability of porous materials and viscous dissipation on an electrically conducting incompressible fluid passes through a vertical porous channel filled with porous materials. One of the plates moves in the flow direction while the other is stationary. The governing coupled flow equations have been solved analytically using Homotopy Perturbation Method (HPM). The influences of the flow parameters on velocity and temperature were plotted on graphs while numerical values for rate of heat transfer and shear stress on the heated and cold plates were presented in tables. Excellent agreements were found when compared with the previous works. It is noteworthy to mention that the hydrodynamic and thermodynamic distributions of the fluid increase with increase in viscous dissipation ( Ec ) . It is also found that the shear stress decreases with increase in the magnetic field ( M ) while a r...

Nonlinear Engineering

This study theoretically investigates the effects of variable viscosity, thermal conductivity and... more This study theoretically investigates the effects of variable viscosity, thermal conductivity and wall conduction on a steady mixed convection flow of heat generating/absorbing fluid passes through a vertical channel. One of the channel plates moves with a constant velocity while the other is stationary. The governing flow equations are solved analytically using homotopy perturbation method (HPM). The effects of the thermophysical and hydrodynamics parameters are captured in graphs and tables. It has been observed that, both the velocity and temperature distributions decrease with increase in viscosity and boundary plate thickness near the heated plate while a reverse cases were observed near the cold plate. Increase in thermal conductivity ε decreases the fluid flow near the heated plate. When the boundary plate thickness is increased, the critical value of Gre to onset the reverse flow increases while increase in thermal conductivity reduces the critical value of Gre. It’s also no...

Afrika Matematika, 2015

ABSTRACT This paper deals with effect of chemical reaction and radiation absorption on the unstea... more ABSTRACT This paper deals with effect of chemical reaction and radiation absorption on the unsteady MHD natural convection flow in a vertical channel filled with porous materials. One of the plate moves with a constant velocity in the direction of fluid flow while the other plate is stationary. A uniform magnetic field acts perpendicular to the porous plate, which absorbs the fluid with a suction velocity varying with time. The dimensionless governing equations for this problem are solved analytically using two-term harmonic and non-harmonic perturbation series method. The results of the analytical solutions for velocity, temperature and concentration profiles of both phases are graphically presented and discussed. It is noteworthy to mention that growing permeability and channel width parameter lead to increase in the fluid velocity profile. Results in the present work have been compared with other works in literature and an excellent agreement is found.