Radiative transfer in an infinite cylinder

The problem of radiation transfer in a cylinder with diffuse reflectivity and containing an energy source is connected with the source-free radiation transfer problem with isotropic boundary condition. Equation for the radiation heat flux is obtained for a polynomial source. In the special case of isotropic scattering, the radiation heat flux is given in terms of the albedo of the second problem. An expression is also given for the net radiation heat flux.     

Padé approximant calculations for dispersive,isotropic scattering,homogeneous media

Exact relations for radiation heat flux at the boundaries of a slab with diffusely reflecting boundary conditions and internal source are obtained in terms of the reflection and transmission coefficients of a source free slab with isotropic boundary conditions. The integral equation defining the radiation heat flux contains explicitly the internal source. So, the particular solution for radiative transfer equation is not required. Available exact values for albedos give exact values of radiation heat flux. Padé approximant technique is used to obtain numerical values for homogenous media.     

An exact similarity solution in radiation magneto-gas-dynamics for the flows behind a spherical shock wave

An exact similarity solution for a spherical magnetogasdynamic shock is obtained in the case when radiation energy, radiation pressure and radiative heat flux are important. The total energy of the shock wave increase with time. We have shown that due to the magnetic field the flow variables are considerably changed. Also, due to increases in radiation pressure number the radiation flux is increased.     

Comparison of heat balance characteristics at five glaciers in the Southern Hemisphere

Ablation characteristics of five glaciers in Patagonia and New Zealand were compared. Investigated glaciers were Tyndall and Moreno in southern Patagonia, Soler and San Rafael in northern Patagonia, and Franz Josef in New Zealand. Micro-meteorological observations were carried out at the glaciers and the heat balance components were estimated. At Franz Josef and Soler glaciers, the sensible heat flux is the largest and the latent heat flux is the second, and they are larger than the net radiation. At San Rafael Glacier, the net radiation is the largest and the latent heat flux is the smallest component, which is similar to Moreno and Tyndall glaciers. Though the latent heat flux is the smallest component at San Rafael Glacier, it is more than twice as large as that at Tyndall Glacier and contributes substantially to ice melting. The ratios of heat balance components were very different among glaciers, but the total heat flux ranged from about 240 to 300 W m⁻² showing little difference among glaciers.     

Anisotropic radiation transfer in a sphere with internal source

In this work we connect the problem of anisotropic radiation transfer in a sphere with diffuse reflectivity and containing an energy source with the problem of source free amisotropic radiation transfer with isotropic boundary condition. Exact equation for radiation heat flux for the first problem is obtained in terms of the source, the flux and the albedo of the second problem. Modeled kernel is used to represent the anisotropy of the phase function. Numerical results are given.     

Radiative and free-convection effects on the oscillatory flow past a vertical plate

The interaction of free convection with thermal radiation of the oscillatory flow past a vertical plate is studied. The Rosseland approximation is used to describe the radiative heat flux in the energy equation.     

Propagation of spherical shock waves in an exponential medium with radiation heat flux

In this paper propagation of spherical shock waves with radiation heat flux is considered in an exponentially increasing medium. The shock wave moves with variable velocity and the total energy of the wave is variable. For different values of radiation parameter, the numerical solution has been made and the nature of the field variables are illustrated by the tables.     

Surface heat current in an inhomogeneous slab with reflecting walls

The problem of radiative transfer in an inhomogeneous finite medium with boundary surfaces which reflects both diffusely and specularly is connected with a source-free specular boundary condition radiation tramsfer. Numerical results are obtained for the partial heat flux using the bi-variational technique.     

The seasonal variation of the thermal structure of the atmosphere of Neptune

Previous work on the atmosphere of Uranus is extended to Neptune. The variation of effective temperature with latitude and season is evaluated within the approximations that the redistribution of internal heat in the interior results in the temperature at fixed pressure near the top of the convective region being independent of latitude and time, and that the transport of heat in the atmosphere is by means of radiation and convection. Meridional heat transport in the atmosphere is neglected. It is found that as the absorbed solar flux varies with season the flux of internal heat varies in the opposite sense such that the variation in the sum of the two is much smaller than the variation in either. The resulting variation in the flux radiated out the top of the atmosphere, which responds to the sum of the internal and absorbed solar fluxes, is substantially smaller than for Uranus because of the much larger flux of internal heat. For Neptune, the time-averaged effective temperature at the pole is ≈0.2°K greater than at the equator and the seasonal variation in the polar effective temperature is ≈0.8°K.     

A self-similar flow of self-gravitating gas behind a shock wave with radiation heat flux,I

Self-similar flows of self-gravitating gas behind the spherical shock wave propagating in a non-uniform atmosphere at rest, taking radiation heat flux into consideration, are investigated. The total energy of the wave is non-constant and can be made to vary slowly with time.     

A Shearing Non-Adiabatic Solution of Einstein's Equations

An analytical solution of the Einstein's equations is found for a collapsing radiating body, consisting of an isotropic fluid with shear undergoing radial heat flow with outgoing radiation. The behavior of the density, pressure, heat flux, mass and luminosity are analyzed for a body of 6 M⊙. This revised version was published online in July 2006 with corrections to the Cover Date.     

Magnetogasdynamic cylindrical shock wave model in an optically thin atmosphere

Similarity solutions for one-dimensional unsteady isothermal flow of a perfect gas behind a magnetogasdynamic shock wave including the effects of thermal radiation has been investigated in a uniform thin atmosphere. The flow is caused by an expanding piston and the total energy of the flow is assumed to be constant. Radiation pressure and energy have been neglected in comparison to radiation heat flux and the gas is assumed to be grey and opaque.     

A study of the expansin of the solar corona with radiation heat flux

The expansion of the solar corona, with the aid of hydrodynamic blast wave theory using the concept of the Roche model, is studied here when both the solar gravity and radiation heat flux are taken into consideration.     

On the nature of the transition region between the solar corona and chromosphere

We have calculated an equilibrium temperature distribution over the column depth of plasma in the transition region between the solar corona and chromosphere by assuming the plasma in the transition region and the chromosphere to be heated by the heat flux from the corona and the energy fluxes from the convective zone, respectively. The corona-chromosphere transition region is shown to be actually a stable, very thin layer in which, however, the standard collision approximation is well applicable for describing the heat flux. The solution we found explains well the currently available results of satellite observations of extreme ultraviolet (EUV) radiation from the transition region.     

Modelling of self-similar cylindrical shock wave in radiating magnetogasdynamics,I

Self-similar flows of a perfect gas behind a cylindrical blast wave with radiation heat flux in the presence of an azimuthal magnetic field have been investigated. The effects of radiation flux and magnetic field together on the other flow variables have been studied in the region of interest. The magnetic field and density distribution vary as an inverse power of radial distance from the axis of symmetry. The electrical conductivity of the gas is taken to be infinite. The total energy of the flow between the inner expanding surface and the shock is assumed to be constant. We also have supposed the gas to be grey and opaque and the shock to be transparent and isothermal.     

Material exchange as heat engine for the corona-chromosphere transition region

We think that a steady material exchange in the upper solar atmosphere can act as a heat engine that cools the corona and heats the corona-chromosphere transition region. We have considered heat conduction from the corona and radiation loss in the transition region and have calculated the temperature, density and velocity distributions in the transition region. Also discussed is the relation between the material flux, the velocity boundary value and the thickness of the transition region.     

The boundary-layer flow of a radiating gas by the integral equation method

The flow in the boundary layer of a very hot two-component plasma is analysed when the radiative heat flux is given by the exact integral equation expression. The basic nonlinear integro-differential equation is solved by perturbing it about the differential approximation for radiation. In this way some light is shed on the order of accuracy of the differential approximation of radiation. In fact an error of about 4% may be incurred by invoking the differential approximation.     

Turbulent Heat Fluxes in the Atmosphere of Venus

A thermal regime of the troposphere of Venus is mainly determined by the greenhouse effect. A closeness of the real temperature gradient to the adiabatic one indicates that turbulent heat fluxes are also essential. Additional problems arise as only about 11% of the solar radiation absorbed by the planet reaches the surface, and most of it is taken up in the clouds at altitudes of 60–70 km. The present study summarizes experimental data on atmospheric parameters related to turbulence and estimates turbulent fluxes and turbulence characteristics. These data confirm the author's hypothesis of an anomalous downward turbulent heat flux in the free atmosphere. A normal upward turbulent heat flux exists in the planetary boundary layer.     

Radiation transfer in a diffuse and specular reflecting slab with Rayleigh scattering

A method of analysis is presented for solving the radiative transfer problem in an absorbing, emitting, inhomogeneous, and anisotropically scattering plane-parallel medium with specular and diffuse reflecting boundaries and internal source (problem 1). Exact relations for the radiation heat flux at the boundaries of problem 1 are obtained in terms of the radiation density and albedos of the corresponding source-free medium with specular reflecting boundaries (problem 2). Two coupled integral equations for the radiation density and the second moment of the radiation intensity for problem 2 with Rayleigh phase functions are obtained. The Galerkin method is used to solve these equations. Albedos of problem 2 are compared with theF _n method. Numerical results for radiation heat fluxes at the boundaries of problem 1 are tabulated for different forms of the internal source.     

Self-similar solutions for the blast wave problem in radiative gasdynamics,I

Similarity solutions, describing the flow of a perfect gas behind spherical shock waves, are investigated including the radiation heat flux. The shock is assumed to be propagating in a medium at rest. Shock radius varies exponentially with time and density is inversely proportional to fifth power of the shock radius immediately ahead of the shock front.