Layering and vertical transport in sheared double-diffusive convection in the diffusive regime

A sequence of two- and three-dimensional simulations are conducted for the double-diffusive convection (DDC) flows in diffusive regime subjected to an imposed shear. For a wide range control parameters, sufficiently strong perturbation conductive initial state, staircase-like structures spontaneously develop, with relatively well-mixed layers separated by sharp interfaces enhanced scalar gradient. Such staircases appear be robust even presence shear over very long times, early-time coarsening observed layers. same set different asymptotic layered states, markedly vertical fluxes, can arise structures. The significantly spatio-temporally modifies transport various scalars. flux ratio $\gamma ^*$ (i.e. between density fluxes due total salt heat flux) is found, at steady essentially equal square root diffusivity thermal diffusivity, consistent physical model proposed Linden & Shirtcliffe ( J. Fluid Mech. , vol. 87, 1978, pp. 417–432) variational arguments presented Stern 114, 1982, 105–121) unsheared convection.