LAUSR

This article reports analytical as well as numerical solutions for fully developed unsteady natural convection in a Couette flow with transfer of mass due to thermophoresis. The time dependent model describes a physical situation which is solved using a finite difference Scheme that is implicit, backward in time and centered in space. The steady state version of the present physical situation has been solved exactly. The influence of controlling parameters on dimensionless velocity, concentration, skin-frictions and Sherwood number are demonstrated through graphs and tables. Graphical results show that Schmidt number should be greater than 0.6 for thermophoresis to be effective in air. The numerical results reveal that the ratio of convective mass transfer to diffusive mass transfer increases with increases in thermophoresis coefficient and time until it finally reaches its steady-state value.