We compute the spectra and fluxes of the velocity and temperature fields in Rayleigh-Bénard convection in turbulent regime for a wide range of Prandtl numbers using pseudospectral simulations on 512(3) grids. Our spectral and flux results support the Kolmogorov-Obukhov (KO) scaling for zero Prandtl number and low Prandtl number (P=0.02) convection. The KO scaling for the velocity field in zero-...

Gravity or buoyancy plays an important role in atmospheric and geophysical flows. The flow is destabilized when heavier or colder fluid is on top of a lighter or hotter fluid, often seen in thermal convection (Fig 1(a)). Convection plays an important role in interiors of many planets and stars, and it is one of the mechanisms for the generation of a magnetic field. Conversely, the flow is stabi...

[1] Hydrographic observations made with an undulating vehicle carrying a CTD and concurrent shipboard ADCP velocity observations over a 12-day period are combined to investigate vertical mixing and cross-frontal fluxes on the Northern Flank of Georges Bank. The CTD density time series is analyzed to detect the presence of vertical overturns, the statistics of which are used to infer vertical mi...

The goal of this work is to examine in detail how turbulence evolves in the presence of both vertical stratification and horizontal (straining) buoyancy fluxes. Horizontal density gradients are a ubiquitous feature of estuarine and coastal flows, as are sheared velocity profiles. The combination of these two features produces a buoyancy flux which can be either stabilizing or destabilizing, dep...

The interaction of thermal radiation with conduction and laminar natural convection in a vertical circular pin, situated at participating gas, is numerically investigated. An absorbing and emitting gas is considered, and treated to be a gray participating media. Under the idealizing of gray gas, the Rosselan4 approximation is employed to describe the radiative heat flux in the energy equation. ...

A new bulk model of the convective boundary layer, the probabilistic bulk convection model (PBCM), is presented. Unlike prior bulk approaches that have modeled the mixed-layer-top buoyancy flux as a constant fraction of the surface buoyancy flux, PBCM implements a newmixed-layer-top entrainment closure based on the mass flux of updrafts overshooting the inversion. This mass flux is related to t...

NOTATION A 'Effective area' in Boussinesq ventilation model, see eqn (24) ,4 'Effective area' in non-Boussinesq ventilation model, see eqn (28) A I Area of floor covered by base of fire a Area of vent B Plume buoyancy flux b Plume radius c r Specific heat capacity at constant pressure D Diameter of fire source d Upper-layer depth F Scaled density deficit, a conserved quantity with units of buoy...

A localized source of buoyancy flux in a nonreactive fluid medium creates a plume. The flux can be provided by either heat, a compositional difference between the fluid comprising the plume and its surroundings, or a combination of both. For autocatalytic plumes produced by the iodate-arsenous acid reaction, however, buoyancy is produced along the entire reacting interface between the plume and...