One-dimensional turbulence: Part 2. Staircases in double-diffusive convection

One-Dimensional Turbulence (ODT), a turbulence model implemented as an unsteady simulation, is applied to the diffusive regime of double-diffusive convection. For this application, no parameter adjustment or other empiricism is required. Computed component fluxes across heat–salt and salt–sugar interfaces are consistent with the Linden–Shirtcliffe picture, applicable at intermediate density ratios, and Newell's model of interface evolution at high density ratios. The experimentally observed onset of a variable regime at density ratios below 2 is reproduced. Simulations of interface formation in a bottom-heated salt-stabilized medium indicate that Fernando's scaling for interface stabilization height may also apply to the height of initial interface formation. The simulations generate staircases resembling those seen in laboratory experiments, and suggest a refinement of a scaling inferred from experiments. Computed results for a thermally forced configuration and an unforced, vertically homogeneous configuration are compared.