In this study, a numerical analysis of viscous, incompressible and electrically conducting fluid in vertical concentric annuli with ramped type motion of inner cylinder has been presented. An applied magnetic field has also been taken into account. The non-linear partial differential equations governing the flow formation have been solved numerically by using implicit finite difference Crank-Nicolson method. The topographies of the flow formation peculiarity have been discussed with help of graphs and table. The noteworthy observations are about the effect of velocity of magnetic field on the velocity profiles of the fluid and skin-friction profiles of the fluid. One of the interesting finding of our study is that when velocity is employed to magnetic field, then effect of magnetic field gets reversed and the effect of velocity of magnetic field get more pronounced with radii ratio. Also, Hartmann number and time parameter have increasing effects on the skin-friction profile. (C) 2017 Elsevier Ltd. All rights reserved.

In this article, a numerical analysis has been performed to study the effect of radial magnetic field on natural convection of a viscous incompressible and electrically conducting fluid within the concentric vertical annuli containing a ramped type temperature profile at the surface of inner cylinder taking into account the induced magnetic field. Two cases are considered which are case 1, when inner cylinder is perfectly conducting and outer cylinder is non-conducting and case 2, has opposite configuration. The governing partial differential equations have been solved by using Matlab software. The influence of Hartmann number and magnetic Prandtl number on different profiles has been presented graphically. It is found that the effect of Hartmann number and magnetic Prandtl number is to decrease the velocity profile in both the cases. This study suggest that the heat transfer can be controlled by using ramped temperature and conductivity of the cylinder.

In the present paper, an analysis has been performed to study the influence of induced magnetic field on the transient free convective flow of an electrically conducting and viscous incompressible fluid over a vertical cone. The coupled nonlinear partial differential equations governing the transient flow have been solved numerically by using the implicit finite difference method of Crank–Nicolson type. The influence of magnetic parameter, magnetic Prandtl number and semi-vertical angle of the cone on the velocity and induced magnetic field profiles has been illustrated graphically. Also, the local as well as average skin-friction and Nusselt number has been presented graphically. For result validation, we have done a comparative study and the present results are found to be in very good agreement with available results.

In the present paper, we deal with the effect of G-jitter (time periodic gravity modulation) on the stability of double diffusive convection in couple stress liquid by method of non-linear analysis. The infinitesimal disturbances are expanded in terms of power series of amplitude of modulation. Couple stress term has been employed in momentum equation. For the stationary convection, the Ginzburg–Landau equation has been used to investigate the effect of modulation on heat and mass transfer. The effect of Prandtl number, couple stress parameter, Lewis number and solute Rayleigh number has also been investigated.