DOUBLE-DIFFUSIVE NATURAL CONVECTION IN A SQUARE POROUS CAVITY WITH SINUSOIDAL DISTRIBUTIONS SIDE WALLS FILLED WITH A NANOFLUID

Double-diffusive convection of a nanofluid in a square cavity filled with a porous medium using Buongiorno's mathematical model is numerically investigated. Sinusoidal temperature and concentration distributions on both side walls are considered, while the gradients of temperature and concentration are taken to be equal to zero on the horizontal walls. The nanofluid particle fraction on the boundary is passively controlled. The governing equations and boundary conditions are introduced in dimensional form and then converted to dimensionless form using suitable dimensionless parameters. The resulting system of equations is solved numerically using a collocated finite volume method with the SIMPLE technique. The obtained data are presented in terms of streamlines, isotherms, isoconcentration, and rescaled nanoparticle volume fraction contours as well as profiles of the velocity components, temperature, concentration, and rescaled nanoparticle volume fraction at the enclosure midsection and local Nusselt number at the heated wall. Comparisons with previously published work are formed and found in very good agreement. It is found that the activity of the nanofluid motion is reduced as the buoyancy ratio is increased.