Two-Scalar Turbulent Rayleigh-Benard Convection: Numerical Simulations and Unifying Theory

摘要

We conduct direct numerical simulations for turbulent Rayleigh-B\'{e}nard(RB) convection, driven simultaneously by two scalar components (say,temperature and salt concentration) with different molecular diffusivities, andmeasure the respective fluxes and the Reynolds number. To account for theresults, we generalize the Grossmann-Lohse theory for traditional RBconvections~(Grossmann and Lohse, J. Fluid Mech., 407, 27-56; Phys. Rev. Lett.,86, 3316-3319; Stevens et al., J. Fluid Mech., 730, 295-308) to this two-scalarturbulent convection. Our numerical results suggest that the generalized theorycan successfully predict the overall trends for the fluxes of two scalars andthe Reynolds number. In fact, for most of the parameters explored here, thetheory can even predict the absolute values of the fluxes and the Reynoldsnumber with good accuracy. The current study extends the generality of theGrossmann-Lohse theory in the area of the buoyancy-driven convection flows.