A Modified Analysis of the Onset of Convection in a Micropolar Liquid Layer Heated From Below

In the present paper, the thermal stability analysis of a micropolar liquid layer heated from below is investigated by utilizing the essential arguments of the modified analysis of Banerjee et al. The principle of exchange of stabilities (PES) is shown to be valid using Pellew and Southwell's method for the problem, whether the liquid layer is hotter or cooler. A general expression for Rayleigh numbers is derived using Galerkin method valid for all combinations of rigid and dynamically free boundary conditions. The values of critical wave numbers and consequently of critical Rayleigh numbers for each case of boundary combinations are derived and computed numerically, when instability sets in as stationary convection. The effects of microrotation parameters and the coefficient of specific heat variation on critical Rayleigh numbers for each case of boundary conditions are computed numerically. From the obtained results, we conclude that the microrotation viscosity coefficient K and coefficient of specific heat variation for large temperature have stabilizing effects whereas microrotation parameter A has destabilizing effect on the onset of convection.