In this paper an attempt has been made to study explicitly the effect of viscous dissipation in the MHD Rayleigh problem with inclined magnetic field is investigated in this paper. Numerical results and graphs are presented to study the combined effect of Hartmann number, Hall Parameter, Rotation parameter, Eckert number, angle of inclination and Prandtl number.
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Introduction:-The study of Magnetohydrodynamics of a conducting fluid has applications in a variety of geophysical and astrophysical problems. The unsteady free-convection flow of a electrically conducting, viscous incompressible fluid have gained considerable attention in the presence of applied magnetic field in connection with the theories of fluid motion in the liquid core of the earth, oceanographic and metrological applications.The viscosity of the fluid in a viscous fluid flow will take energy from the motion of the fluid and transform it into internal energy of the fluid. That means heating up the fluid. This partially irreversible process is referred as dissipation or viscous dissipation. Viscous dissipation is defined as the irreversible process by means of which the work done by a fluid on adjacent layers due to the action of shear forces is transformed into heat.The effect of viscous dissipation in natural convection was analyzed by Gebhart [1]. Iqbal et.al [2] studied the viscous dissipation effects on combined free and forced convection through vertical circular tubes. Hossian [3] studies the effect of viscous and Joules heating on the flow of an electrically conducting fluid past a semiinfinite plate when temperature varies linearly with the distance from the moving edge and it in the presence of a uniform transverse magnetic field. Vajravelu and Hadjiniwlaou [4] analyzed heat transfer in a viscous fluid over a stretching sheet with viscous dissipation and internal heat generation. The problem of heat transfer on a moving plate with a uniform magnetic field has attracted the attention of many researchers such as Ali [5], Takharet. al. [6] and Zakaria [7].The simultaneous effects of the heat transfer and Hall current on a MHD flow with a porous medium in a rotating system was investigated by Dileepsing [8]. Loganathan [9] analyzed the viscous dissipation effects on unsteady natural convective flow past an infinite vertical plate with uniform heat and mass flux. In all the above cases either normal or horizontal magnetic field is considered, but this cannot support the entire physical scenario. In Science