Unsteady Mixed Convection Flow of a Micropolar Fluid About a Sphere

Abstract

An analysis is presented to investigate the unsteady flow and heat transfer characteristics of mixed convection flow of an electrically conducting micropolar fluid about a sphere. The transformed governing equations of the nonsimilar boundary layers are solved using the finite difference method. We also utilize the series solution method for short time and the asymptotic method for long time. A comparison is made between the numerical and the series solutions, which provides a good agreement. Numerical solutions have been carried out for a wide range of the mixed convection parameter, the vortex viscosity parameter, the spin-gradient viscosity parameter, the heat generation or absorption parameter, the conduction-radiation parameter and the magnetic field parameter. The effects of these parameters are discussed in terms of the variations of the local friction factor, couple stress and Nusselt number. Also we compare the present solutions with the existing results and found to be an excellent agreement.