Abstract: In the present paper, the investigation to the mixed convective boundary-layer behavior over a horizontal plate is carried out. By applying transformation group theory, the analysis of the governing equations of continuity, momentum. energy and diffusion shows the existence of similarity solution for the problem provided that the temperature and concentration at the wall are proportional to x^4/(7-5n) and that the moving speed of the plate is proportional to x^(3-n)/(7-5n), furthermore, a set of similarity equations is obtained. The similarity equations are solved numerically by a fourth-order Runge-Kutta scheme. The numerical results obtained for velocity,temperature and concentration distributions for Pr=0.72 and various values of the parameters Sc, K₁, K₂ and K₃ reveals the influence of these parameters on the flow,and heat and mass transfer behavior.

Key words: mixed convection, group theory, similarity solution