The system considered in this study is the twodimensional vertical porous layer subjected to aconcentration difference AC and a temperaturedifference AT in the horizontal direction (Fig. 1). Thefluid-saturated porous medium is treated according tothe homogeneous model [2] coupled with theBoussinesq approximation that accounts for smalldensity variations due to both temperature andconcentration changes at constant pressure. Thedensity variations can be expressed as