Unsteady Free Convection From A Sphere in A Porous Medium With Variable Surface Temperature

In this paper a transient free convection flow around a sphere vith variablesurface temperature and embedded in a porous itiediuln has been considered. thetemperature of the sphere is suddenly raised and subsequently maintained at values thatvaries with position on surface. the method of asynlptotic expansions is applied for sltial1rayleigh numbers and then a finite-difference scheme is used to solve the problemnunlerically for finite values of rayleigh numbers. transient and steady-state flow andtemperature patterns around the sphere are discussed in details and a comparison betveennumerical and analytical results has been presented.