Multi-component convection-diffusion with internal heating or cooling

The onset of convection in a fluid layer with an internal heat source is st udied. Tn addition to the temperature field there are present two different , dissolved salt fields. Thus, this paper investigated the effect of an int ernal heat source on the problem of triply-diffusive convection. The effect of the boundary conditions is found to be important. For two surfaces free of tangential stress a disconnected oscillatory neutral curve can be found which has the same minimum as the stationary convection one. Thus the poss ibility of simultaneous initiation of convection by two different mechanism s, but with two different aspect ratios, is found. It is also found that th e above effect is present when the lower surface is fixed while the upper s urface is free of tangential stress, even if the container of the fluid is of finite horizontal extent. When both surfaces are fixed we have not obser ved the twin minima effect.