NONLINEAR STABILITY PROBLEM OF A ROTATING DOUBLY DIFFUSIVE POROUS LAYER

Lyapunov direct method is applied to study the non-linear conditional stability problem of a rotating doubly diffusive convection in a spars ely packed porous layer. For a Darcy number greater than or equal to 1 000, and for any Prandtl number, Taylor number, and solute Rayleigh nu mber it is found that the non-linear stability bound coincides with li near instability bound. For a Darcy number less than 1000, for a Prand tl number greater than or equal to one, and for a certain range of Tay lor number, a coincidence between the linear and nonlinear (energy) st ability thermal Rayleigh number values is still maintained. However, i t is noted that for a Darcy number less than 1000, as the value of the solute Rayleigh number or the Taylor number increases, the coincidenc e domain between the two theories decreases quickly. (C) 1995 Academic Press, Inc.