Resonance of Double-Diffusive Convection in a Porous Medium Heated with a Sinusoidal Exciting Temperature

Laminar double-diffusive convection in a two-dimensional porous square cavity differentially heated and salted is studied numerically. The left vertical wall of the cavity is heated with a temperature varying sinusoidally in time, while the opposite cold wall is maintained at a constant temperature. The same walls of the cavity are salted with constant and different concentrations (the concentration of the heated wall is higher than that of the cooled one). The remaining horizontal walls are considered adiabatic and impermeable. The parameters governing the problem are the amplitude of the variable temperature (0 <= a <= 1), its period (0.0001 <= tau <= 10), the buoyancy forces ratio (-5 <= N <= +5), the Lewis number (0.1 <= Le <= 10) and the thermal Darcy-Rayleigh number (R-T = 400). Effects of these parameters on fluid flow, temperature and concentration distributions and mean heat and mass transfers within the cavity are analyzed. Results obtained show that both heat and mass transfers could be significantly enhanced or reduced, with respect to those generated in the case of constant heating conditions by proper choice of the parameters related to the periodic temperature.