Combined Effect of Temperature Modulation and Rotation on the Onset of Darcy-Bénard Convection in a Porous Layer Using the Local Thermal Nonequilibrium Model

Thermal convection in a Newtonian fluid-saturated horizontal porous medium is studied using the linear stability analysis in the present study. The porous medium is uniformly rotating about a vertical axis, and the fluid and porous matrix are out of thermal equilibrium. The horizontal boundaries are assumed to be subjected to time-periodic temperatures with heating from below. The extended Darcy law, which includes the Coriolis force and time derivative terms, is used to model the linear momentum conservation equation. A deviation in the critical Darcy-Rayleigh number is calculated as a function of governing parameters, and the impact of those is illustrated graphically to understand the effect of modulation on the onset of convection, mainly when the porous matrix and fluid are not in local thermal equilibrium. It is noted that, at low-frequency symmetric modulation, the instability can be enhanced by rotation. In contrast, in the case of asymmetric modulation, the stability can be enhanced by rotation.