ON MICROPOLAR FLUIDS HEATED FROM BELOW IN HYDROMAGNETICS IN POROUS-MEDIUM

The thermal instability of electrically conducting micropolar fluids h eated from below in the presence of uniform vertical magnetic field in porous medium has been considered. It is found that,the presence of c oupling between thermal and micropolar effects, magnetic field and per meability may introduce oscillatory motions in the system. The increas e in Rayleigh number for stationary convection and decrease in Rayleig h number for overstability with the increase in magnetic field is depi cted graphically. Also the Rayleigh number is found to decrease with t he increase in permeability.