FINITE FREQUENCY EXTERNAL MODULATION IN DOUBLY DIFFUSIVE CONVECTION

Convective oscillations in porous and fluid media are studied numerically. A two-dimensional, square, differentially heated cavity, filled with a porous medium saturated by a binary fluid or simply by a binary fluid, is considered. This cavity is subjected to linear harmonic oscillations in the vertical direction. The formulation is based on the Darcy-Brinkman-Forchheimer-Boussinesq model. The time dependent Darcy-Brinkman-Forchheimer-Boussinesq equations are solved using a pseudo-spectral Legendre collocation method. The instantaneous and mean characteristics of the flows are studied and discussed. An intensification of the heat and mass transfers is observed at low frequency for sufficiently high vibration intensity. A comparison between the response to the imposed vibrations is made for Darcy numbers varying from Da = 10 -7 to Da = 10.