The effect of variable gravity on rotating Rayleigh–Bénard convection in a sparsely packed porous layer

Abstract

AbstractThe effect of variable gravity on rotating convection in a sparsely packed porous layer is studied numerically. For gravity force variation, the linear, parabolic, cubic, and exponential functions are considered. Boundary conditions for the governing equations are considered to be either free or rigid. The normal mode method is employed, and the resulting eigenvalue problem is solved numerically for free–free and rigid–rigid boundaries using bvp4c in MATLAB R2020b. The influence of Darcy number (), gravity variation parameter (), and Taylor number () on the stability of the system is investigated graphically. It is confirmed that the gravity variation parameter and Taylor number delay the onset of convection and Darcy number enhances the onset of convection. The size of convection cells decreases on raising the variable gravity parameter and rotation parameter, while the Darcy number amplifies the size of convection cells. It is also observed that the system is stable for exponential gravity function and less stable for the cubic gravity function.