The formation of layered structure by the imposition of an unstable buoyancy flux on a region containing opposing, uniform gradients of two components is examined. TURNER (Journal of Fluid Mechanics, 33, 183-200, 1968) investigated the formation of layers when a stable salinity gradient is heated from below. The present work is an extension of his, allowing for the presence of a destabilizing t...

In the major ocean basins, diapycnal mixing upwells dense Antarctic Bottom Water, which returns southward and closes the deepest cell of the meridional overturning circulation (MOC). This cell ventilates the deep ocean and regulates the partitioning of CO2 between the atmosphere and the ocean. Our conceptual understanding of the deep stratification and MOC has evolved from classic “abyssal reci...

It has been recently recognized that the nonisothermal conditions present in physical vapor transport ampoules can give rise to a slip flow of gas over the side walls of the ampoule. This phenomenon, known as thermal creep, is usually insignificant relative to buoyancy-induced flows under similar nonisothermal conditions, and has therefore been neglected in previous PVT numerical models. Howeve...

Motivated by the problem of the formation of active regions from a deep-seated solar magnetic field, we consider the nonlinear three-dimensional evolution of magnetic buoyancy instabilities resulting from a smoothly stratified horizontal magnetic field. By exploring the case for which the instability is continuously driven we have identified a new mechanism for the formation of concentrations o...

In this paper we present a unified shell model for stably stratified and convective turbulence. Numerical simulation of this model for stably stratified flow shows Bolgiano-Obukhbov scaling in which the kinetic energy spectrum varies as k(-11/5). The shell model of convective turbulence yields Kolmogorov's spectrum. These results are consistent with the energy flux and energy feed due to buoyan...

We study shallow moist Rayleigh–Bénard convection in the Boussinesq approximation in three-dimensional direct numerical simulations. The thermodynamics of phase changes is approximated by a piecewise linear equation of state close to the phase boundary. The impact of phase changes on the turbulent fluctuations and the transfer of buoyancy through the layer is discussed as a function of the Rayl...

We study in this paper the correlation between buoyancy flux, efficiency of energy dissipation and linear nonlinear components potential vorticity, PV, a point-wise invariant Boussinesq equations, contrasting three identified regimes rotating stratified turbulence, namely wave-dominated, wave–eddy interactions eddy-dominated. After recalling some main novel features these flows compared to homo...

Rayleigh-Bernard convection offers a unique flow situation in which buoyancy-generated turbulence can be studied in isolation, free of the complicating influence of shear production of turbulence. The objective of this paper is to examine and model important aspects of buoyancy-generated turbulence using direct numerical simulation (DNS) data of Rayleigh-Bernard convection. In particular, we ex...

We discuss nucleosynthesis results obtained following the recent suggestion that extramixing phenomena in red giants might be driven by magnetic buoyancy. We explore for this model the production of the short-lived radioactive isotope Al and of stable light nuclei, considering both the case of the general buoyancy of flux tubes and that of the intermittent release of magnetized unstable structu...