The double-skin roofs investigated in this paper are formed by adding a metallic screen on an existing sheet metal roof. The system enhances passive cooling of dwellings and can help diminishing power costs for air conditioning in summer or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers are investigated. Depending on its surface properties, the...

The standard equilibrium for radiation-dominated accretion disks has long been known to be viscously, thermally, and convectively unstable, but the nonlinear development of these instabilities—hence the actual state of such disks—has not yet been identified. By performing local two-dimensional hydrodynamic simulations of disks, we demonstrate that convective motions can release heat sufficientl...

In a di erential equations course, one typically studies a few classes of problems for which there are closed form solutions, such as ordinary, linear di erential equations with constant coe cients. Most problems of interest in real world simulation problems are much more complex, however, involving domains of two or more dimensions or nonlinear e ects, yielding partial di erential equations or...

The size distribution of moist regions in the tropical atmosphere exhibits two modes of organization, one at synoptic scales and the other at planetary scales. We show the existence of these two modes in two data sets: columnintegrated precipitable water and outgoing long-wave radiation. A simple two-column model of radiation and convection in the Tropics helps interpret the presence of these t...

The convection-radiation effects in thermal fluid flows are studied based on the Lattice Boltzmann method. Nine-velocity flow and temperature distributions are used to obtain the mass, momentum and energy equations in thermal incompressible flows by studying equivalent moment systems. The radiative heat flux in the energy equation is obtained using the discrete-ordinates solution of the radiati...

We discuss prospects of using multi-dimensional time-dependent simulations to study the atmospheres of brown dwarfs and extrasolar giant planets, including the processes of convection, radiation, dust formation, and rotation. We argue that reasonably realistic simulations are feasible, however, separated into two classes of local and global models. Numerical challenges are related to potentiall...

We study magnetohydrodynamic radiation-convection flow through a porous medium with mass transfer in the presence of a homogeneous first order chemical reaction and surface temperature oscillation. The governing equations are solved analytically using perturbation technique. Detailed computations of the influence of Hartmann number, frequency of the oscillation, radiation parameter, Prandtl num...

Based on many previous experiments, the most efficient explicit and stable numerical method to solve heat conduction problems is leapfrog-hopscotch scheme. In our last paper, we made a successful attempt nonlinear conduction–convection–radiation equation. Now, implement convection radiation terms in several ways find optimal implementation. The algorithm versions are tested by comparing their r...

Drying is a simultaneous heat and mass migration phenomenon in which water phase transition occurs based on energy transfer by conduction，convection, radiation.

We have calculated the radial non-adiabatic p-mode oscillations of the solar models. Based on a statistical theory of non-local convection, both the thermodynamic and kinetic couplings between convection and oscillations are finely treated. The turbulent pressure, turbulent viscosity, turbulent thermal flux and turbulent kinetic flux are all self-consistently included in the equations. The depa...