Unsteady laminar MHD flow and heat transfer in the stagnation region of animpulsively spinning and translating sphere in the presence of buoyancy forces

An analysis has been carried out to determine the development of momentum a nd heat transfer occurring in the laminar boundary layer of an incompressib le viscous electrically conducting fluid in the stagnation region of a rota ting sphere caused by the impulsive motion of the free stream velocity and the angular velocity of the sphere. At the same time the wall temperature i s also suddenly increased. This analysis includes both short and long-time solutions. The partial differential equations governing the flow are solved numerically using an implicit finite-difference scheme. There is a smooth transition from the short-time solution to the long-time solution. The surf ace shear stresses in the longitudinal and rotating, directions and the hea t transfer are found to increase with time, magnetic field, buoyancy parame ter and the rotation parameter.