Double diffusive convection in the finger regime for different Prandtl and Schmidt numbers

In this work fingering double diffusive convection, i.e. the buoyancy-driven flow with fluid density being affected by two different scalar components, is investigated numerically with special efforts on the influences of the physical properties of two scalar components. We show that different scalar properties can affect the global transport behaviors. The concentration flux exhibits different exponents in their power-law scalings for different combinations of scalar components. The scaling exponents of heat flux, however, depend mainly on the ratio of the diffusivities of two scalars. If one uses the local parameters of the finger layer in the bulk, the behaviors are very similar to those found in the fully periodic simulations. The horizontal width of the fingers is consistent with the wavelength of the fast growing mode. For one case we observe evidences of the thermohaline staircase, namely, the typical width of the flow structures changes significantly in different layers within the flow domain.